Photographing art with G2

[DWard]

I am trying to come up with the best procedure for making record photographs of our artwork. It is mostly oil on canvas with some watercolors under glass and some prints under glass.

The G2 has some barrel distortion at wide angle. It also seems not to be sharp. Seems like the auto focus has difficulty.

I am using a tripod with the remote control to eliminate camera shack. I also have two 420EX strobes with an ST-E2 and position them at 45 degrees. Can also use umbrellas if need be to soften light.

Suggestions for assuring sharp focus and minimizing distortion?

Thanks

David

[Harv]

Sounds like your most of the way there.

Just don't use the camera at a wide angle setting, zoom out to what would be at least 50mm and even better at 80mm (35mm equivilent).

Oil paintings can reflect light from any angle, especially if it has texture.

You can defeat this entirely and also increase the saturation by using polarizing filters. Not just one on the camera lens, but also over the flashes as well. You can find polarizer filters in sheet form, though they are expensive. The sheets will always have an arrow that indicates the grid direction within the filter. Just make sure that the orientation is the same over both lights, then just turn the lens filter until you get maximum effect. This will eliminate all glare. It's an amazing difference and well worth it. If you can't tell where to turn the lens filter, just shoot four images, turning the filter 1/4 turn at each shot. The darkest image will be the maximum effect.

This technique works for both strobe and continous lighting equally well. You will lose a lot of light, perhaps up to 3-4 stops worth. The lights do not need to be a true 45degrees off the center of the subject, but the closer you are to 45 degrees the better.

You should not need to soften the lighting at all.

[DWard]

Harv,
Thanks for the suggestions regarding polarizing the light.

The painting I am using for testing is oil, but not highly reflective, although others are.

Some of the painting, including the one I am testing with are quite large approximately 60 by 60 inches. This makes the longer focal length more difficult to achieve without having to unhang the painting and set up a special shooting area in the living room. That is probably the best solution. Will use a smaller piece for testing.

Thanks again,
David

[Harv]

The greatest thing about digital photograpy is being able to see your results immediately!

Hot lights are actually a lot easier to use, and being a northerner I can say - very nice in the winter!

I used to shoot a lot of paintings for our Art museum on campus (MSU), some being very large and shooting 4x5 transparencies. You need a lot of strobe power for larger pieces since you need to have the strobe placed fairly well back from the painting. I would be concerned that you may run out of strobe power with the 420's especially on the 5x5 work. I would also be concerned that the strobes may produce hotspots, which could force you to use diffusion and then lose more light. If you use the polarizers, you may be in an impossible situation. Hot lights gives the ability to use a real long shutter speed to make up for lost light.

You can even go to a hardware store and get the cheapest shop light style reflector heads you can find and drop in fairly powerful bulbs, clamp them to a stand or a chair or whatever and put the polarizers about 12" in front and that may be a solution for less than 20 bucks (not including the filters).

Also, use a grey card or a grey/color chart card, this will help you balance the colors later.

A great reproduction of original art is worth the hard effort.

[DWard]

Harv,
I agree with your suggestion about the "hot lights" if the intent is to create an image that is intended for reproduction. In that case I would also use 4x5 or 8x10 transparency file. (I did that sort of thing 30 years ago as a commercial photographer.)

The goal here is to provide digital images that are as sharp and color accurate as possible for view on a computer or printing on 8X10 for reference purposes.

I would also like the kit to be portable enough to take to a gallery to photo work we are contemplating on purchasing.

BTW, this whole thing started when a gallery in NY sent us some really poor digital images of work and expected us to make a purchase choice. Then was amplified when my wife was in NY and took a couple of digital shots with on camera strobe and ambient light of two pieces so we could discuss when she got back.

The polarizer suggestion will go a long way toward helping. To get better color accuracy I have picked up a Q-13 Kodak color separation guide and gray scale to include in the shots.

My biggest concern is that the G2 seems to lack something in sharpness when doing this sort of thing.

The large images will be an infrequent occurance, while the mobility of the strobe lighting will be a significant convenience.

Thanks again Harv,

David

[Harv]

Ah, gotcha. You have to love a large format trans though, eh?

I agree that sharpness on prosumer digital cameras is lacking. How savvy are you with Photoshop? Convert your image to LAB color, select the "lightness" channel and apply sharpening there only, then convert back to RGB. This does less damage to the file than sharpening within the RGB color space.

Also, sounds like your travel kit is correct. You could consider the minisoftboxes for shoe mount flashes, just attaching polarizing filter over the box. Not so much to soften the light, but to minimize hotspots.

Sounds like you have your share of fun. Good luck!

[DWard]

Harv,
Thanks for the tip about LAB channel. I have been using PhoteShop Elements V2. Not sure if it has that ability. Also not sure how sharpening will impact the image.

Yes I did love the large format transparencies. That probably is part of the frustration here. I did so love the Kodachromes I made with my Leica and Nikon gear. (That was back in the days when Canon was considered to be "amature" gear.) 2 1/4 Ektachrome was the minimum for anything that was going to a printer.

This digital stuff has gotten me reinterested in photography as a hobby after all these years. But the old desire for sharp, snappy images with perfect color is still there I guess.

Happy Holidays Harv ( and all those following the thread)

David

[PatrickEggers]

Make sure you are taking a RAW image, maximum pixels, minimum compression. Back your camera up until you can zoom in at a minimum of 80mm and preferably at 105mm to eliminate the lens distortion (true of portraits, as well). Experiment with "sharpening" in your software. This should give you the desired results (the polarizing filter is a good idea as well).