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Thor734 · Joined: 09 May 2005 Posts: 18

I am looking for some sugested setting for my digital rebel. I will be attending an Airshow and I am still having a difficult time with depth of field. I have been playing with this camera(my first dslr) for a while and am having a difficult time with this. I have the stock EF-s lens that ships with the camera plus the 75-300 usm Mk III lens. I am hopeful of a nice sunny day, but that may be too much to ask for:)

What I am looking for is some starting points to get a good depth of field to capture the stationary planes from close up(10-20 ft) and maybe farther away moving (1-2 thousand feet). These will be failry large aircraft as it is a military air show.

As I understand DOF a smaller f-stop will generally give a larger DOF.
For the close up shots I am thinking aroung f-11 or smaller.
For the farther away shots I am thinking even smaller, but I suspect that may not be correct.

I realise that more goes into getting a correct exposure and DOF, but as I may not get this "behind the scenes" opportunity again, I'd like to maximixe my chances of getting some decent shots.

I have googled DOF and read many article on it, but I am still having trouble using it in the "real" world, hence my desire to get pointers on a starting point, from there I can wreck the pictures on my own......lol

These forums are a great learning tool, along ofcourse with the people that answer the questions............

Thanks
Rob

StuartE · Posted: Tue May 17, 2005 2:10 am

Rule of thumb, use a mid range aperture, as narrow as the light will allow, unless you're looking for 'creative' depth of field - that way you'll get as much DOF as you can, which will result in less rejections for 'noise/focus/upsize'

You need to counter that with the need for shutter speed on the moving objects, e.g., planes in flight...

Try for around the f/8-f/11 to start with, see how it goes...

Most importantly, SHOOT RAW, and shoot often - take as much of the show as you can - if you want speed, get familiar with shifting the program for more DOF, and shoot in P mode... 1/3 of a stop under to make sure you get highlights, and shoot like a mad thing...

Cheers,
Stuart

Forgiss · Posted: Tue May 17, 2005 4:49 am

Ditto everything that Stuart said...

Don't worry about DOF for planes in flight... the further your subject is away from you, the larger your DOF, so shoot there to get good exposures...

on the 75-300 I would be scared to go below f/8. In my experience sharpness tends to deteriorate rather rapidly below f/8...

I do not know how close you are allowed to the planes, but f/8 and f/11 will suit the day 90% of the time except if the light acts up...

Thor734 · Joined: 09 May 2005 Posts: 18

Thanks for your excellent suggestions.
One other question: For the fast moving planes should I use iso 200 or maybe 400 or 800?

Thanks Again
Rob

Forgiss · Posted: Wed May 18, 2005 1:40 am

Try to keep your speed up, by all means, but the 300D doesn't like sunshine above ISO 100 (meaning areas of sun and shade) 200 will still work ok but on 400 you are going to start picking up serious noise (not a problem unless you want to submit images for SS)

MHD · Posted: Wed May 18, 2005 1:49 am

Yeah, for planes, unless you are in REAL trouble, the space they occupy is much less than thier distance from you so you can pretty much shoot as open as you want...

Judging from comments you lens is a cheaper cannon lens (sounds equiv to the 70-300G type Nikkor) I know that the nikkor is damn soft wide open (f.3.5-5.6) and gives the best pics at ~f/7

I loose most of my tele pics from hand shake, I strongly suggest using a tripod or monopod...

Thor734 · Joined: 09 May 2005 Posts: 18

Thanks for the great replies.

Rob

Remyrw · Joined: 15 Feb 2005 Posts: 171 Location: Slidell, LA

Think of it as a sliding percentage. The smaller the f/stop used the bigger a percentage of the total distance you can get. This is why macro photography tends to be very tough on depth of field while landscapes are no problem. For an example I'll use the piece of junk zoom sitting next to me since it has the guides on it. It's a 35mm-135mm f/3.5-f/22 clunker from Nikon, an old manual focus model.

At 35mm f/11 it will get 8 feet to infinity in focus if focused at the right point (around 15' away.)
At 135mm f/22 you can only get even get from 30' to infinity in focus and the closer your start point for focus the smaller the range gets. Focused at 8' you might get from 7.5' to almost 10' in focus, still at f/22.

So, your problem won't be anything far enough away to be flying, it's when trying to take pics of the planes you're standing in front of in the display area. I'd go for as small an f/stop as you can and put that puppy on a tripod to allow the slower shutter speeds if the sun doesn't cooperate. Also, try to minimize the total distance you need sharp, shoot the plane at an angle rather than more head on if you can. A 45 degree angle shot just cut your needed depth of field in half (at least for the fuselage of the plane).

To make it more complex, depth of field starts where you focus and extends both directions. It doesn't extend equally though. Generally speaking you get a much shorter distance heading toward the camera than away, thus the general empahasis on distance X to infinity for depth of field. For example, if I set that zoom to 35mm and want the nose of that plane I'm 6' away from (the closest point I want sharp is 6') then I can focus on a point 8.5' away at f/11 and get everything from 6' to around 20' in focus. This requires testing with your lenses to know how quick the fall off is and whether that scale is accurate.(if your lens even has one) The lens I'm actually referring to is fuzzy at the best of times, and I know that at the edges of what it considers in the dof range things will get blurry quickly so I should bias to the inside of that range. Anyway, you will get a feel for this over time, but remember that it's not a fixed point and then past that a fixed amount based on the f/stop, it's a fixed point you focused at then a variable amount that includes the f/stop, lens length, focus distance, and lens design. Your lens might have come with a chart outlining this for you, if not I'm sure someone has published the chart even if the lens maker hasn't.

This information is one of the key differences between many pro lines and the consumer models. Pro lenses tend to have distance/DoF information built into the lens, which is why I could just pick up the lens and "focus" it to a particular distance and see what my dof would be with various settings without even using a camera. To really have this click and get a feel for it you just have to mess with it. Try shooting a set of pics of something angling away into the distance, like a picket fence or even just train tracks (for longer distances, for close stuff even a pencil works great) and focus on the middle of it and start shooting one pic after another, changing the f/stop one stop at a time. Then try focusing much closer and do it again. If you're using zooms, do this at the wide, medium and long settings to see how the results change with your lens. If you really were getting serious you could log this information on a notepad and keep it handy for reference when depth of field was of critical importance. Of course, that requires something suitable to measure with. I used to keep a marked wire in a spool for this kind of thing when I used a view camera. Once the camera was set up you could easily see and manipulate depth of field, but it was a real pain to set up and find out you needed to back up ten feet or use a different lens and be ten feet closer.

Remyrw · Joined: 15 Feb 2005 Posts: 171 Location: Slidell, LA

General airshow tip.
Unless it's an overcast day without a really bright sky, when taking pics of the planes in flight you usually want at least 1 stop over exposure, otherwise the planes come out really dark and you get a great shot of the sky. :)

Obviously if the plane is close enough to be a big part of the frame you can ignore that. For dimmer skies it's not as big a problem, but I'd still test out a few shots early on and make adjustments before the real show starts so you don't miss a shot you want because you're trying to get something other than the sky and a plane's silhouette.

Thor734 · Joined: 09 May 2005 Posts: 18

Thanks for all the help. Here are a few lessons I learned the hard way as usual:

1. If you remember to bring a hat for shade, remember to bring one for your wife also, lest you end up with no hat :).

2. Planes moving at 500-600 mph are very difficult to photograph.

3. Always remember to delete old pictures on your memory cards before you begin taking picture of a new event.

4. If your memory card seems un usually small, see item 3.

5. Never forget sun screen.

6. Never forget sun screen.

7. I did not over expose enough.

8. DOF was less an issue than correct focus was. Between my small pair of glasses and the smallish view finder on the EOS Rebel, it was difficult at best to get good focus. I sometimes found myself looking over the rim of my glasses which did not help.

Here are some of the ones I liked best:

Remyrw · Joined: 15 Feb 2005 Posts: 171 Location: Slidell, LA

Pretty good for a first try at that type of work, and given the difficulties you had. The trick with focus that I probably should have mentioned, was to forget autofocus or even manual, pick an f/stop, set the lens to focus from infinity in as close as you can at that f/stop, and the make sure it stays there. Chances are that plane is far enough away to be perfectly focused that way and there's no delays. At least if it's flying that's the case. Sometimes the really close passes are different but it's almost impossible to track them with a camera anyway once they're close enough for it to be an issue. As you said, 500+mph basically makes following it with a regular camera a real trick.

Thor734 · Joined: 09 May 2005 Posts: 18

Couple more:

Thanks again for all the great advise.

Thor734 · Joined: 09 May 2005 Posts: 18

How do you set it for infinity? There are no markings on the lens and as I understand it, Canon lens will focus past infinity. I've read that other lens physically stop at infinity.

Thanks
Rob

Thor734 · Joined: 09 May 2005 Posts: 18

Forgot to post the most interestin one:

Remyrw · Joined: 15 Feb 2005 Posts: 171 Location: Slidell, LA

You actually want to focus just before infinity so your depth of field includes it. Your best bet if you don't have markings is to do it by eye ahead of time.
Again, this is why pro lenses are often worth the extra money.