View Full Version : Having a close focus problem

Greg Davis
1-Aug-2012, 13:22
I am trying to photograph a curio cabinet full of junk. The cabinet is very shallow, only an inch deep, but it is in a narrow hallway. Because I am so close, I am using my 210mm Apo-Symmar. The bellows are drawn out, but not to 1:1. The lens is about 18 inches from the cabinet, so I have stopped down to f/22 to gain as much depth of field as I can with out diffraction. Where I am having problems is that the center and corners are sharp, but the middle areas are definitely not. I figure this is just a limit of this lens design, so I thought I might try my 210mm Componon-S instead to see if it has a flatter field, but I wanted community input before wasting more verynexpensive 8x10 color film.

1-Aug-2012, 16:27
210mm Componon-S seems like it would have a flatter field. Another thing to experiment with is increasing the cell spacing of the Apo Symmar by unscrewing the front element. It could make it better or worse. There is no easy way to decrease the lens spacing, however.

Greg Davis
8-Aug-2012, 09:29
I tried it today with the Componon-S. I have both an Apo-Symmar and Componon-S of the same focal length, so I took the Symmar out of the shutter and replaced it with the Componon-S and rephotographed the box. It is much sharper throughout the image. The Apo-Symmar, while a great lens at infinity, created a "water drop ripple" type focus effect. The Componon-S was sharp throughout. Before placing it in the Copal 1 shutter, I used my digital calipers to measure the overall length of the lens, then screwed it into the shutter and ensured the overall length matched the original. As it happens, it was screwed all the way into the shutter. Being the same focal length, I used the aperture scale on the shutter and the density is excellent.

I thought this might be a solution after reading your thread on small prints using different lenses and how the fields weren't flat at those close ratios. I am going to contact print this negative and then print it at a 1:1.125 ratio with a few different FL enlarging lenses and see if any perform better than others, or if I need to get the copy lens I asked about in a different thread.

Greg Davis
14-Aug-2012, 05:13
So I have a good, sharp negative from this cabinet now. I have never tried printing an 8x10 negative smaller than 16x20 unless contact printing, but I want a set of prints on 11x14 paper with a 1 inch border on the short side, so an image area of 9 x 11.25. This is a 1.125x enlargement, way below the 2x minimum stated by Schneider for their Componon-S lenses. I wanted to see how well my current lenses would print that small before investing in a copy lens for this purpose. I tried the 300mm lens first and compared it to a contact print. Here is a shot of both the contact and the enlargement from the 300mm lens. This is not the entire image, but a 4x5 inch section of the upper right hand corner, but they extend almost to the center. I focused very carefully on the center of the image and stopped down to only f/11. I did not worry too much about matching density and color with this sample, but the darker one is the enlargement. They are printed on matte paper and then scanned at 300 dpi, reduced to 96 dpi for uploading, so take what you will from that. I am hard pressed to see much, if any, difference in the two. I was planning on comparing my 210mm and even 150mm lenses at this magnification to see if they performed better, but I am not sure if that is necessary now. Any thoughts?