G Claron & other process lenses

[Jim Andrada]

Hi Geoffrey.

A couple of the photos have "been around" as they say. There's a bit of a story to two of them. The guy with bottle (Charlie) was walking down the street supporting his elderly and a bit infirm mother and carrying her doll(???) for her. She went into the house behind the blue door to visit a friend and Charlie got to talking with us, so I asked if he'd like his picture and he thought it was a great idea so he pulled out the bottle as a gag (I suspect he pulled it out more often when it wasn't a gag.) Anyhow he hung out with us for a while. You can probably tell from the photos that this wasn't your ordinary everyday neighborhood. In fact a lot of the buildings were condemned but folks were living in them anyhow. They were basically living among an amazing number of scrap metal and recycling companies just North of Boston. Then one fine day in 1973 a fire got started that destroyed 18 densely built acres. They claim that nobody died, but I often wonder if anyone thought of all the "invisible" people who were more or less "squatting" in abandoned buildings. It was a fascinating place. https://en.wikipedia.org/wiki/Great_...a_Fire_of_1973

[Lachlan 717]

This might help to get an idea on how sharp the 355mm G Claron is.

The monofilament is about 20m/60' away in this shot. Sorry about the crap way I've presented this; I'm no good with PS (this took me an hour!)

Attachment 140968

[Old-N-Feeble]

Lachlan... that's not a crap visual aid at all. In fact, it's better designed and illustrated than most will take the time to do.

[Lachlan 717]

Thanks, O-N-F. I hope that it conveys just how good this lens is...

[Old-N-Feeble]

It does and it's impressive, IMO. Could you do a similar illustration showing far edge performance?

[Lachlan 717]

Will do. Stay tuned!

[Geoffrey Poulton]

The question for process lenses at infinity is "will the entire horizon be in focus." That is the working definition of "flatness of field" for non-process lenses. From the flat film's frame of reference it is as if the horizon is curved. Your best bet is to use the standard "defocus/diffraction" focus method of Hansma to get the entire curved image in focus. Tilt and hyperfocal focusing are not the best answers to the problem at hand. Downward front tilt makes it worse; with a process lens, the edges of the scene focus too close to the camera making the grass is in focus but the horizon is blurry at the edges before you apply any tilt. Hyperfocal focusing is something out of a handbook on small format hand-held photography and usually of no benefit to large format photography on a tripod.

Thanks very much for these thoughts. I'm used to using a Hasselblad and have found that I (almost) automatically go to hyperfocal focusing. If I set the hyperfocal distance say for f8, I then turn the aperture to f11 to take advantage of the extra depth of field. With the 5x4 I usually use forward tilt with my other non-process lenses.

I shall remember this advice and also to look up the defocus/diffraction" focus method of Hansma - which I'll do after posting this. No doubt I will be directed back to this thread!!

[Geoffrey Poulton]

This might help to get an idea on how sharp the 355mm G Claron is.

The monofilament is about 20m/60' away in this shot. Sorry about the crap way I've presented this; I'm no good with PS (this took me an hour!)

Attachment 140968

Thanks for this, it certainly not "crap" as you term it, and it does give a good indication of the excellent resolution of the lens, even on the internet. The photograph itself looks a nice piece of work too - you must have been pleased to discover that scene, the mist possibly enhances it too, as does B&W.