Depth of Field Question

I am planning to take some pictures of my N Scale layout and have a couple of questions related to depth of field.

My equipment is a Canon 20D and have a 100 MM Macro lense and two telephoto lenses; 28-88, and 75-300 MM zooms.

I have just enough knowledge to be dangerous. I have done some experimenting with the macro lense and using an aperature opening of 32. The DOF is good but the focus (image sharpness) is not as sharp as I'd like it.

Question 1: Related to focus, is it better to use the macro lense with a large aperature (small opening) up close, or a telephoto from a distance ( the farther the distance the larger the DOF I believe)?

Question 2: Is it better to use hi wattage lighting, flash, or lower wattage lighting, or a combination? My experimenting using a 300 watt lighting source with some backlighting to soften shawdows resulted in reflections of the white and light colored objects.

Any help would be greatly appreciated.

 

I, too, have a little knowledge, but have been determined to be dangerous by nobody but myself.

With the 100mm lens, I think you need to have the camera much further away from the subject than with a 60mm to be able to focus. On the lighting, and after taking only about 100 shots with a macro, I found that just a little light, diffused throughout the room and the smallest apeture and a long exposure time gave me the best results. No flash at all since there will be light bouncing back off the subject. Ignore the framing and below see with, if I remember correctly 500 watts off the ceiling, f32 and a longer than normal exposure time. Please ignore tilt. Low wattage, I believe, is best with a longer shutter speed.

 

Piute:

Don't use a flash at all taking photo's of your layout.

With a 1:1 macro lens you can focus on yoour object from a distance of one inch. Focus on your object. That will be in foucus and the background will be out of focus.

When you're taking photo's set your camera to manual operation and your f stop to 32.

You'll need a tripod to take the picture as your exposure time will be dramatically increased.

You should use a tripod on all your photo's.

Set your timer to take the photo or else your camera will move when you take the photo.

You have to practice taking different photo's at different distnaces and f stops. You'll see a marked improvement as you become more comfortable taking photo's.

Stay cool and run steam.....

 

I forgot say, photography is a lot about compromise to get the shot you want. To make the picture you want you have to decide which compromises you want to make to get the shot you want, ie. sharpness, DOF, scene compression, etc..

[ December 31, 2005, 04:21 PM: Message edited by: RED ROCK ]

 

Thank you all for the information. Having a digital camera, I can afford to experiment with various combinations of aperture settings and shutter speeds until I find a good combination.

Also called Canon for some advice. Seems DOF is a major issue with many photographers.

 

Plute,

With a Canon 20D, you can use a flash. Just make sure you've got aperture priority, and the deepest f-stop set, such as f/22. And also that your flash can crank out enough light.

I'm using a Nikon D70 with a Nikon Speedlight SB-800. I bounce the flash. I'm setting the Speedlight to plus 2 stops compensation. That is, it's cranking out four times the light it thinks it needs. It works fine!

The "don't use flash" mantra is really a result of the point-and-shoot and automatic cameras, which usually use a wide f-stop like f/5.6 for flash pictures, thereby destroying depth of field.

With the 20D, you can shoot flash at f/22. Or use multiple flashes, still a f/22. Does the 20D even have a on-camera flash? If so, I doubt it's strong enough to shoot at f/22. Again, it's my experience that, when I bounce the flash, which is about the only quick way to soften the light, it takes a full 2 f-stops of compensation to get enough light onto the subject.

 

I am surprised no one has mentioned the software in Rich Yourstones article in the latest issue of NSR...Helicon Focus Software...

The images put even the best HO images I've seen to shame.

 

Helicon Focus is a software package that allows you to combine images of a scene with the focus set at different spots. The camera obviously must be on a tripod--that's a given, anyway. It sorts through the panes for best focus in each, and then combines them into one image with nearly unlimited depth of field.

People love it! It takes a little fooling around to get accustomed to it, as Rich alluded to.

It's available for Windows machines for $115 (Lite) to $250 (Pro). The Lite version is probably all that you need.

I'm buying a PC Windows emulator for my Mac tomorrow, just to use this software.

Plute, I realized I never directly answered your questions.

Q1: for depth of field, you'd probably want to use the widest lens you have at its smallest f-stop (f/22 or f/32). Now, the sharpness of some lenses degrades noticeable at small f-stops.

Q2: There's no short answer to this. It's a matter of adjusting light until the highlights don't blow out, and the shadows maintain detail. Sometimes that's one light with maybe a reflector card; and other times it could be many lights. I have a multi-deck layout, so throwing light between the decks is a real problem. The top deck is easier to shoot, believe me.