Because of the happenings during this past weekend's Weekend Photo Fun, I thought I would put together a tutorial for taking good, quality photos fo your models and layout. I will be the first to admit, I am not professional photographer, nor did I stay at a Holiday Inn Express last night but I think I get good results with what I have to work with. I plan to discuss things like f-stop, shutter speed and their inter-relationship, depth of field composition, equipment needed, lighting and others as appropriate.
Because this will be about photography it will be a photo intensive thread - be forewarned if you have a dial-up connection. This is not meant to be a thread for posting photos just for the sake of posting pics, but a thread were people will hopefully learn a little bit about taking pics to show off their work.
So in the spirit of things to come, here's a starter/teaser pic.
I hope people enjoyed and don't find it to be a waste of bandwidth.
Simon Modelling CB&Q and Wabash See my slowly evolving layout on my picturetrail site http://www.picturetrail.com/simontrains and our videos at http://www.youtube.com/user/MrCrispybake?feature=mhum
Yes, good idea. Another person explaining things using different words and with different photos may make things "click" where they didn't before.
-Crandell
I had a tutorial on model photography on this forum several times in the past. I've placed it and more on a separate wesbite, see in my signature below.
There is a page on myself and my photography if anyone needs credentials.
Bob Boudreau
CANADA
Visit my model railroad photography website: http://sites.google.com/site/railphotog/
Bob's tutorials are excellent. I recommend that anyone save the links to his and hopfully leave space here for something really important.
I haven't been on dial-up for about 12 years now, so how long does it take someone with a 56k modem to download the picture posted in the first post? (It's 155+k, is why I asked.)
First things first, I do not have a bunch of expensive specialized equipment. My basic equipment consists of the following
With these four things, a pencil, a notepad and a little patience you can achieve very good results.
Here's what I be working with.
This a my tripod and a piece of white poster board to use as a backdrop. Nothing facy about either one. A nice feature to have on your tripod is the ability to tilt the head to change from landscape to portrait format.
This a basic mini-mo module I built from some scraps I had around. Total construction time was about 3 or 4 evenings to go from nothing to finished scenery. It only about 11 inches wide and about 40 inches long. It's easy to move around. I have other modules also to use for picture yaking. It sits atop my radial arm saw table with the arm swung out of the way. Attached to the table is an ordinary desk lamp on a swing arm. Nothing fancy, easy to find at the local office supply store or discounter. I like because I can move the base around on the table and then adjust the arm to get the light where I want it. When I'm not taking pictures I use it as my work table light. I have a second swing arm light with a magnifying glass it. If I feel I need more light I can add that to the mix, but I've never found it necessary.
I'm thinking of creating a sub-album in my Photobucket to place all the photos into so as not to clog up the thread. I would allow everyone to see the bracketed range of pics without overloading the thread.
Next discussion - cameras and camera settings.
The starter/teaser pic was taken last fall using my son's 4-H module. I found a place towards the back of our development where no houses had been built yet. I thought the trees would make a good background without being out of scale. The module was set on a couple of folding sawhorses in the street. Again I used the tripod even though there was bright sunlight shining from the west. I didn't take notes of the camera settings but in this case because of the natural light I probably used the camera's automatic setting.
All of the pics I will use are the actual, unedited pics. In my opinion if you have to rely on editing software to make your pics look good then you're doing something wrong to begin with.
A little more background. As I said, I am not a professional photographer by a long shot. I learned how to use a camera by using a good old fashioned 35mm SLR that I bought with my HS graduation money. I took a B&W photography course in college that taught you how to use your camera, composition and how work in a darkroom developing your own film and making your prints. Doing so taught you how to use light to the best of your advantage. You soon realized that no matter how hard you tried if your negative was crappy and not in focus, your print would never be since you actually focused the enlarger on the grains of silver in the negative. What I'll share is based on my experiences.
Well, I've got pics to upload and label. More to come.
Neutrino wrote: Bob's tutorials are excellent. I recommend that anyone save the links to his and hopfully leave space here for something really important.I haven't been on dial-up for about 12 years now, so how long does it take someone with a 56k modem to download the picture posted in the first post? (It's 155+k, is why I asked.)
It took about 2.5 minutes
Jerry SP FOREVER http://photobucket.com/albums/f317/GAPPLEG/
GAPPLEG wrote: Neutrino wrote: Bob's tutorials are excellent. I recommend that anyone save the links to his and hopfully leave space here for something really important.I haven't been on dial-up for about 12 years now, so how long does it take someone with a 56k modem to download the picture posted in the first post? (It's 155+k, is why I asked.) It took about 2.5 minutes
Thanks Jerry. That was the point I was trying to make. If you're going to do a photo tutorial, you should be posting pictures in the 50-75 kb or smaller range so that those with dial-up don't grow a beard while waiting to look at a picture.
I warned people in the original post that this was going to be a photo intensive thread. There will be a lot of pics used to show the results of different lighting and camera settings. Reducing the file size will reduce the image quality and make it harder to tell the difference in pics from different camera settings. One of the objectives is to use unedited pics to show that good results can be achieved without software tricks. Most of the pics will be in photobucket but there will be a lot in the thread too. Sorry, but I won't sacrifice showing higher res images for download speed. If you're on a dial-up connection then you know in advance that it will take some time to load up.
CAMERA BASICS
The first thing you need is a good digital camera. As with many things, the more the better rule applies. The more megapixels, the more features on the camera, the more you can do with the camera. Unfortunately, the more rule also means the more it costs. You can still get a good digital camera that can produce good results for around or less than $100.
Some of the features to look for on a digital camera are:
A digital camera with have a lot more features and settings, but using just these basic items exceptional results can be obtained. Will they magazine publishing quality, probably not, but they will allow you to show off your work.
I've decided to put most of the photos into a photobucket album so that the thread doesn't become overloaded with pics. There will still be pics included in the thread as examples, but the bulk of the photos will be available through photobucket.
Lighting is next
selector wrote:2.5 mins to download 200k is way too long. Something else is going on. I could see it taking that long to get a 20 post page loaded, but not one photo of that size.
On sustained downloads, I get about 5.5 kilobytes per second from most servers. That works out to about 40 seconds for a 200 kb image.
I have rural phone lines and don't get the federal regulated 53 KBPS one might in an urban area. My ISP always notes astonishing levels of noise and dropped packets when we chat, and most connections eventually negotiate to about 44kbps regardless of connection speed at the start.
I was uncomfortable with this thread when it began, since it might be seen as focusing on one board member in particular, but that member, while not as...crusty...as some here, seems to hold his own well, and there is the potential for useful discussion in a thread like this, so I hold judgement for now.
Regarding the information presented to date, I agree with the self timer recommendation, but be advised, it uses a LOT of battery power in and of itself, and because it spaces out time between shots, while the power consuming LCD display decimates normal alkaline cells.
I use the self timer because my camera came with one, but some of the newer models use tiny remotes, saving battery power, and a simple standard shutter release button, threaded to accept a standard shutter release cable, eliminates camera shake without using up battery power at all.
Finally, regarding image processing, whether in the camera, pre-image-capture, or in software based applications, my opinions differ from those this thread's author.
That genii's out of the bottle, and in my opinion, has been since the advent of poly contrast filters and papers, maybe even since the first darkroom tech figured out that longer baths in Dektol bring up density and contrast.
Whether for publication, competition, or just personal enjoyment, all imagery is going to be judged on the basis of the individual viewer's sum total of experience with other imagery, and the average user is unlikely to know whether an image has been processed or is displayed raw from the camera.
I doubt if there is EVER going to be complete consensus on what techniques are "legal" and what techniques are "unfair", even in the professional realm. This is a battle that began long ago, and which will continue for as long as photography remains an artform.
In my opinion, there are only two "crimes" in photography:
1. Allowing the possibilities that processing affords to supercede good technique and a continual effort to improve one's technical skills and knowlege,
2. Saying you didn't, when in fact you did.
Note that number two does not, in my opinion, require automatic disclosure, or even disclosure on request.
I do not, as a matter of habit, specify every single detail of the process used to model a scene or to produce images online for same. Mostly I figure that's just TMI and boring.
I do use post production processing, sometimes to fix problems with an image, after identifying same and figuring out ways to avoid the effect in the future. I also use it to get around some basic and inherent limitations in the digital and film based photographic processes.
In no way do I consider this unfair, any more than I'd consider it "unethical" to use slide film over negative film, or an E6 process over Cibachrome in development.
In my opinion, it is all part of the art, from how you time your shoots within the spectra of available light, how you compose and expose them, how you develop and crop and even select them for publication or display.
"Absolute truth" and "absolute fidelity" DO NOT EXIST in photography, in any meaningful or definable way. Even in news photography there are ways to improve, or even "spin" an image and ANY false or physically impossible set of arbitrary restrictions is merely a feel-good panacea for those attempting to implement them.
Far better, in my point of view, to recognize that photography is inherently a SUBJECTIVE process, and to strive to master ALL ASPECTS of the production chain in order to produce the BEST IMAGES within your ability. Anything less, in my opinion again, is an abdication of skill.
That said, I will almost invariably answer, to the best of my ability, any questions raised about the personal production processes used in my photography. MOST of my posted images have been corrected for exposure, full and differential, possibly color balanced, probably spotted, and possibly sharpened. Most also have been taken under the ideal lighting for color temperatures and exposure, within the range of efficiency and expediency, and errors of composition and other concerns addressed BEFORE exposure.
I DO NOT use photographic technique to create modeling effects that are not there, or to hide modeling errors or omissions or mistakes, UNLESS this is specifically noted in text accompaning the posted images. To do otherwise, in my opinion, is "cheating". The only time I remember doing this was noted, when I posted a thread "auditioning" various backdrop images. I see a lot of images, both online and in print, that add steam and smoke effects to digital imagery. I've never done this myself, not because of the ethical considerations, but because I don't think the technique "works" very often, in my opinion the image looks better without fake smoke in most cases.
In my opinion, all of these techniques and more, are well within the bounds of photography as an art form.
In no way does this policy advocate deception. If you take steps to improve your imagery, by means "fair" or "foul", by whoever's imprecise standards, then you either 'fess up when asked, or refuse to answer at all. Claiming you "didn't", when you "did" is a lie, no if's, and's, or but's.
For this tutorial, I agree that post-processing would be counter-productive, at least in the early stages anyway. Later on, a description of post-production techniques might be useful.
In any event, there's a big difference between "counter-productive", and "unethical", whether such claims are actually stated or merely implied.
Post production processing in digital imagery is a fact of life. Whether YOU choose to use it or not, you can either master it, abdicate the skill and knowlege entirely, or pretend it doesn't exist.
Regardless of your choice, I'm reasonably certain that post production processing figures largely into most, if not all major publications relating to the hobby of Model Railroading, and if you have any aspirations along those lines, you either learn it yourself, hope somebody else can do it for you, or else sit on the sidelines while the big dogs play.
Like it or not, that's today's reality.
Jeffers,
I agree that some post processing for digital photos is not only here to stay, it's really a big help. I don't know much about all this but I have some Kodak software that's able to take a picture and lighten it up overall while still maintaining the correct contrast. It has saved a bunch of pics that otherwise would have been unuseable.
What's done, and how much is done, with digital pictures is really an ethical issue for professional photographers. At what point could you have just done the whole shot on Photoshop instead of freezing your buns off trying to get that killer shot of the full moon? I've seen some shots in MR that I suspect had an awful lot of manipulation done to them. That's not always a bad thing but sometimes it shows layout details that really aren't there to the naked eye.
Interestingly, we used digital cameras a lot in law enforcement to document things like accident scenes. However, if a photo was going to be submitted as evidence, the evidence techs still used 35 mm SLR's with film and we had to submit both the print and the negative to the court to have it accepted as evidence. I guess the courts don't trust all that digital manipulation either.
jktrains wrote:I warned people in the original post that this was going to be a photo intensive thread. There will be a lot of pics used to show the results of different lighting and camera settings. Reducing the file size will reduce the image quality and make it harder to tell the difference in pics from different camera settings. One of the objectives is to use unedited pics to show that good results can be achieved without software tricks. Most of the pics will be in photobucket but there will be a lot in the thread too. Sorry, but I won't sacrifice showing higher res images for download speed. If you're on a dial-up connection then you know in advance that it will take some time to load up.
I think this will be a very interesting thread for both broad band and dial up forum members. Why not make two sets of each pic, one small (50-75K) for dial up members, and provide a link for those who want to see it full size? My guess is the 800x600 pics in this thread aren't anywhere close to what the full size pics are anyway, so why compromise..?
Just a thought...
BTW, great topic!
To All Interested Forum Members:
In order for this tutorial to work smoothly I'm asking that unnecessary chit chat be avoided so that the thread doesn't become bloated with non-relevant posts. At the end of the tutorial would be the proper time to post your opinions about items in the thread. I'd like to keep any reply posts to relevant questions about the topic of the posts. For example, "How do I determine what f-stop to use for a pic?"
Maybe the solution is to start a separate thread for discussing various opinions and leave this thread to ore of the how to's. Thanks what I'd like to have happen.
Regarding posting smaller pics and larger pics. I'm going to keep with my original plan. There will be 'large' pics posted as part of the thread. NOt all the pics available will be posted, just samples. A photobucket album will contain all the pics so that one can choose whether they want to spend the time waiting for them to load. Using smaller pics will be counterproductive because part of what I want to show is the differences between settings on a camera. I think you'll lose this on snmaller pics.
jktrains
I took at look at photo and it is 900 (after download) 640 x 480 @ 180DPI Approx 3.5" x 2.6". That could be why and the server could be running slow right then?
Ray Seneca Lake, Ontario, and Western R.R. (S.L.O.&W.) in HO
We'll get there sooner or later!
THE TOPIC FOR TONIGHT IS LIGHTING
Disclaimer
Before we get to that I want to remind people that I am warning you upfront that this will be a photo intensive thread. That's what it says in the subject, that's what it will be. Rather large photo files so people can see the details. More pictures willl be in a photobucket account so that the thread is not entirely clogged. Also, this is meant to be a tutorial, examples of what I found that works without requiring expensive cameras, lights, accessories or editing software. it is not meant to be a highly technical discussion about the pros and cons of various techiniques, but more a presentation on basic concepts to move someone away from simply pointing and clicking and then wondering why the pic didn't turn out right.
Now on to the topic - LIGHTING.
Lighting for photographic purposes is different than room lighting and general layout lighting. The first thing to remember is that you must have light to take a picture, even night shots must have some kind of light in/on the scene. Cameras come with a built in light meter that measure the light reflected from an object that enters the lens. Some cameras with show you the light reading. My old 35mm SLR has a meter on the side of viewfinder image.
A little physics lesson to start with. Imagine an object on a table with a light bulb 1 foot away from it. A light meter placed in front of the object will measure the amount of incident light. Your set your camera's exposure settings, say a shutter speed of 1/250th sec and take a picture of it. Now you move the light another foot away so that it is 2 feet from the object. The amount of light now falling on the object has been reduced to 25% of the original amount. Light intensity dminished follow the inverse square principal, i.e when you double the distance the amount of light received is 1/4 of what it was. Now to take the same picture the shutter speed must reduced not in half but by 1/5 to 1/60th sec. Doing this will allow the same amount of light to reach the 'film' or CCD.
So the distance between the light source and the subject is critical. Because most people's layouts are around 40-48" tall, lights in the ceiling are 36"+ away from the subject. This is typically too far away to provide effective lighting. Enter the swing arm desklamp. I can position this were I need it by clamping it to the benchwork or fascia. With the swing arm I can adjust the distance the light is from the subject.
The wihte background is simply a piece of foamcore board. Its primary purpose is to provide a non-distracting background. It also provides some fill lighting from the light reflected off of it. From the pic you can see that the light is around 18" away from the subject.
The other part of lighting is what light bulb to use. Different types of light bulbs produce different types of light in different temperature ranges. My personal preference that I found is to use daylight compact flourescent (CF) light bulbs instead of regular incandescent bulbs.
On the left is a standard 60 watt light bulb. The desklamp has a maximum recommended bulb wattage of 60 watts. On the right is a daylight 9 watt CF. As the packing insert states it is the equivalent of a 40 watt incandescent. Note that CF are made with various light temperatures. I like the daylight adjusted bulbs becuase they produce a nice white light meant to simulate daylight.
This picture was taken using the 60 watt Incand. light bulb with a .25 sec expsoure at f8.0 (more on this later). The overall light level is good - the white numbers are still white, but not too bright, the black on the loco is black yet you can still make out the details. The shadows can be seen, but you can still make out the detail on the trucks instead of losing the detail in the shadows.
The above picture was taken with the 9 watt CF at the same exposure settings. It maybe a bit darker than the first because of the 60 watt vs. 40 watt equivalent. Notice that the light is 'whiter' than the incandescent, making for a more natural looking light, IMO.
Here's another example
The first was with an incandescent bulb; the second a 9 watt CF. Each pics used the same exposure settings. Notice how much 'whiter' the stripes appear and how brighter the overall image is; the gray and the red are truer to the actual model.
Well, in summary, good photo results require good, adequate lighting. The more light you have, the more ability you will have to make adjustments to the camera's exposure settings. You'll have more range to work with when taking pics of you work. You'll need someway of getting light on the subject you want to photograph. I like the swing arm lamp, you can also use clamp lights with a reflector on them, but you won't be able to simply clamp them to the floor joists in the basement. You'll end up with the light source being too far away - remember the inverse square rule. Use a 1x2 stick clamped to the floor joist to bring the light down closer to your subject.
Give the daylight CFs a try. You can get them at most home centers. The other nice thing about them is that they produce very light heat. They generate a brighter light than incandescents and fit the same screw in sockets.
Next we'll get into f-stops and shutter speeds.
Excellent thread, as you say listen & learn! Can't wait for the rest, thanks!
Nigel
F-STOP AND SHUTTER SPEED
With the point and shot cameras that have popular for so many I think that most people don't consider the two primary exposure variables of f-stop and shutter speed when taking pictures. Instead they let the camera take over and pick what is believed to be the best combination of those two controlling variables.
F-STOP
F-stop is a measurement of opening of the lens in relation to the focal length of the lens. This is not meant to be a technical discussion of photography, so let's just call it an indicator if how openand how much light the lens will allow in when the shutter is triggered. The f-stop of the lens, or camera, is a measurement of how 'fast' the lens is. A 'fast' lens will let in alot of light and allow the photographer to use a higher shutter speed. The f-stop controls the depth of field of the image to be taken.
F-stop is measured numerically. There are standard f-stops that you will see as you adjust your camera's settings. Standard f-stops are f2.8, 4, 5.6, 8, 11, 16, 22, and 32. An f-stop setting of 2.8 is a very wide open lens setting. F22 is a very small openning letting in very little light. Each increase in f-stop along that scale results in 1/2 of the amount of light to pass through the lens. For example a change from f5.6 to f8 cuts the amount of light passing through the lens by 50%. The opposite is also true, a change from f5.6 to f4 allows twice the amount of light to pass through the lens.
SHUTTER SPEED
Shutter speed is measured in secs or fractions of a second. It indicates how long the shutter will be open, allowing light to strike the photosensitve recording device such as film or CCD for a digital camera. As with f-stop an increase or decrease in the shutter speed will allow more or lense to strike the 'film'. Shutter sppeds can vary from 1/1000th sec to infinite where the shutter is held open for a indefinite time period. Most digital cameras do not have a 'bulb' setting but can be set for a sutter speed of a number of seconds. This is used for low light photography.
EXPOSURE CONTROL
Using these two variables, one can override the cameras automatic settings and control the exposure settings of the camera. You can achieve the same amount of light striking the 'film' by adjusting the two variables. For example a setting of 1/125th sec at f5.6 will allow a specific amount of light to strike the 'film'. You could adjust the shutter speed to 1/250th, which will cut the amount of light in half, to correct for the faster shutter speed you would need to open the lens more by change from f5.6 to f4. If you took a picture at each of these settings the light levels would be the same, only the depth of field will have changed. The important thing to remember is that if you desire to maintain the same light level what you do to one variable you must do the opposite to the other variable.
BRACKETING
My personal experience is that must camera light meters are not extremely accurate when used for model photography. When taking photos of your models is best to use a bracketing technique to determine the optimum exposure settings. Bracketeing involves changeing one of those variables one step and a time picture by picture. One of those shots should have an optimum exposure. My preference is to choose the f-stop setting I want to use and to adjust the shutter speed.
Here's an example
The photo is other the same subject and setup as before. Picture was taken at 1/10 sec @ f8.0
This is too dark. You can make out the details on the black part of the body nor can you make out any detail in the shadows or the truck sideframes.
At the opposite end of the spectrum is this photo taken at 1 sec @ f8.0.
In this pic everything is washed out. Sure you can see the truck sideframes now, but the foreground grass is lost and you can't see the detail in the ballast. The exposure time is too long. Goldilocks says that somewhere in the middle must be 'just right'
This one was difficult to chose. The right exposure is something of a personal choice based on what you want to have the pic look like. I picked this one at 0.40 sec @f8.0. I was between this and 0.25 sec.
Now you can see the truck sideframe detail, makeout the individual grains of ballast, the foreground isn't washed out and the detail in the hood can still be seen.
Now that I've picked at satisfactory combination I can use that and the knowledge of the relationship between shutter speed and f-stop to take more pictures. Remember though that if you reposition the camera and change its distance to the subject, the intensityif the light reaching the camera will ahve changes based on the inverse square rule. In the photos above the camera was about 17" from the subject.
To summarize, f-stop and shutter speed co-exist to determine the exposure setting that works best for situation at hand. Use bracketing to take a number of pics of a range of exposure settings so that you get the right exposure, neither over nor under exposed. Since we'll using digital cameras, there's no wasted film, no wasted developing costs and no delay in seeing the results of your work. Also, remember that it's easier to bracket a number of shots than take one or two shots, go back to your computer and look at the image on the large screen, determine that the exposure isn't acceptable and have to go back and set everything up again. So get out and practice some bracketed shots. To see the full range of bracketed shots go to photobucket.com and search for jakrueg then Phototutorial/bracketing.
DEPTH OF FIELD NEXT
Here's a link to the photobucket site
http://s161.photobucket.com/albums/t201
DEPTH OF FIELD
Depth of field means how of the foreground and background will be in focus. it is an effective tool that can be used to soften and blur items in front of and behind the main subject.
Depth of field corresponds to the camera's f-stop opening. A small f-stop number, i.e. f2.8, will produce a very short depth of field. A large f-stop, say f22, will produce a very wide depth of field.
This picture was taken using a f2.8 setting. The camera was made to focus on the front of the locomotive. Note the sharpness of numberboards. The 1 is a just a little blurry, while can't make out the 3 or the 4.
This picture was taken using a f8.0 setting. Again the camera was tricked into focusing on the front of the locomotive. Note of the front details of the loco are sharp and in focus. The one is still in focus, just a little fuzzy. Now you can make out the 3 and with a little effort the 4 behind it.
Unfortunately, my digital camera can only go to f8.0. My film camera has lenses that can go up to f22 which would significantly increase the depth of field of the image.
Remember that one of the trade-offs for increasing the depth of field is a decrease in shutter speed for a longer exposure time.
Also remember to bracket your exposure. Pick a f-stop setting and use various shutter speeds so that you make sure you get a shot with correct lighting. Again, if after you're done there are shots you don't like simply delete them from the card and have at it again.
One more thing I forgot to mention in the post with the photobucket link. If you want to see the detailed caerma settings for any picture, just click on the 'Show Exif Data' when viewing the individual pictures. WARNING - Most of the images are 1024x768 and may take awhile to download over a dial-up connection. I purposely left them as large files so it was evident that the fuzzyness of the image was from the camera settings and not because of the image resolution. This is especially true for the depth of field pics.
Well, there are some other subjects to cover such as low light situations and composition, but before we get into those I wanted to open things up for questions/comments. I appreciate everyone holding back until now. I wanted readers to be able to see each topic without going through the comments.
I also wanted to try and cover these basic topics before the weekend so people can experiment over the long weekend and post their top pic(k)s in WPF.
One more thing about depth of field.
Because f/Stop is a ratio, depth of field decreases as focal length increases. So as you zoom in the portion of the picture in focus narrows. While these aren't MR photos, they illustrate the phenomenon. Both pictures where shot at f/5.6...
70mm lens:The leaves behind the flower are in focus, and you can sorta make out the grass. Note, I cropped this photo, to give it close to the same field of view as the 300mm photo below.
300mm lens:The leaves here are blurred, and the grass blends together in a green mass.
Nick
Take a Ride on the Reading with the: Reading Company Technical & Historical Society http://www.readingrailroad.org/
This, as written, is probably a little confusing for people not familiar with the concepts:
An f-stop is the relationship between the iris opening and the focal length. It is expressed as a fraction.
"f2.0" should actually be written as f/2.0, or "focal length divided by 2".
"f22" should actually be written as f/22, or "focal length divided by 22".
Since something divided by 2 is bigger than that same something divided by 22, f/2 is a "bigger" aperature than f/22, and lets in a lot more light.
1/2 is bigger than 1/22.
Depth of field, then, does not really "correspond with the camera's f-stop opening".
Depth of field, instead, varies inversely with aperature. A large aperature, like f/1.8 or f/2, yields a very short depth of field, while a very small aperature, like f/16 or f/22 yields a very long depth of field.
Big hole, short focus.
Tiny hole, long focus.
Sometimes you just want one thing to be sharp, and everything closer or further away should be blurred out.
That's when you choose a large aperature. You can take pictures of animals at the zoo, and with a large enough aperature (and enough light to avoid motion blur or camera shake), the bars or fence will blur right out of existence, making a much more natural photograph, even as if the animal was photographed in the wild.
Other times you want everything in the picture to be sharp. That's when you use a small aperature.
A long train, coming at or away from the camera, might be a good time for a small aperature, if you want the whole trainlength in focus.
Hope this helps explain why a large aperature has a smaller denominator, and vice versa, and helps clarify the proper relationship between aperature and depth of field.
This is good. I'm learning another aspect of model RR'ng.
Regards,
Tom
After reviewing everything I realized forgot one IMPORTANT TIP
When discussing lighting I forgot to mention TURN OFF THE FLASH! A camera's flash is designed to be effective between a specific range. Typically the distance between the camera and the subject is too close for the flash to be effective. All you'll end up with a very washed out image. Turn off the flash, use your tripod and lengthen your exposure time.