G Claron & other process lenses

[Geoffrey Poulton]

G Claron lenses are detailed as being capable of infinity focus when stopped down to f22.

When taking landscape images I almost invariably use forward tilt and a degree of hyperfocal distance focusing.

When the G Claron lenses (etc) are described as capable of infinity focus at f22, does this refer to the lens already having been focused out to infinity or take into account a degree of focusing employing hyperfocal distance?

Knowing the official explanation of this is probably more helpful than trying to work it out by taking a number of shots to see the effect, which is quite expensive where 5x4 film is concerned and which may not lead to a better understanding.

Extra stopping down beyond a certain point is not usually a good idea either.
I'd be grateful if anyone has any information on this or even the definitive answer.

Thanks Geoff

[Kevin Crisp]

There are certainly dozens of threads on this subject. Use your G Claron just like any other lens. They are sharp at infinity at f:22 and f:16 in my experience with virtually the entire line up. I suspect infinity looks just fine at f:11 too, but I haven't actually tried that. You don't have to stop them down to get a sharp image at infinity. There is no "effect" to see and test for. If you really must test, take one photo at infinity at f:16 and you'll see what I mean.

Several people have reported that the later ones are optimized for more distant objects but I've not seen anything official on that. My experience is with new and old versions.

[Kevin Crisp]

http://www.largeformatphotography.info/forum/showthread.php?9113-G-Claron-is-it-as-sharp-as-a-lens-optimized-for-infinity&highlight=claron+infinity

[djdister]

My 270mm G-Claron is extremely sharp - I use it for landscapes and other detail studies, typically at f/16 or 22. You should just take it out and shoot with it...

[Corran]

I could be misinterpreting but it sounds like you are asking whether or not the lens will have a sufficient image circle when employing hyperfocal focusing and/or tilts.

If so, generally the answer is yes, of course depending on the focal length you are using. The GC lenses are well-known for very generous image circle specs.

If your question is about image quality, well, I think that's also a foregone conclusion - excellent all around.

[Kevin Crisp]

I interpreted the question as starting from the position that the lens couldn't handle infinity, but could you still get there by stopping down. But I could be wrong.

[Drew Wiley]

Just because G Clarons were originally advertised for closeup tabletop photography and were especially well corrected for this doesn't mean they're any less suitable for infinity than a general-purpose plasmat. In fact, they're even better than most at infinity, even at f/11, though smaller stops like f/22 are more frequently employed due to other issues like film plane flatness, variations in subject plane relative to swings and tilts, etc. They're wonderfully versatile lenses
in the field.

[dave_whatever]

Just because G Clarons were originally advertised for closeup tabletop photography and were especially well corrected for this doesn't mean they're any less suitable for infinity than a general-purpose plasmat. In fact, they're even better than most at infinity, even at f/11, though smaller stops like f/22 are more frequently employed due to other issues like film plane flatness, variations in subject plane relative to swings and tilts, etc. They're wonderfully versatile lenses
in the field.

+1 this.

[Luis-F-S]

I'd waste the 4x5 film since everyone responding may not know anymore about the question than you do.

[Drew Wiley]

Nonsense, Luis. I've been shooting and printing G-Claron images for decades, both color and b&w. So have a quite number of other people on this forum.

[djdister]

My G-Claron lens can certainly focus at infinity at f stops wider than f/22. The fact that the Schneider lens info chart shows technical specs (image circle, angle of view) at f/22 is not due to a focusing inability at wider f stops.

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[Drew Wiley]

As I've pointed out before, the spec sheet for G-Clarons followed the tradition of process lenses, from which they evolved. So the coverage given is VERY conservative and geared to very precise apo dot standards at the corners of the field. These are higher standards than used for for general photography specs.
For example, I routinely use my 240 G-Claron for wide-angle 8x10 shots with reasonable wiggle room for tilts and moderate rise, despite what the tech sheet states. And I get quality suitable for seriously big enlargements. With 4x5 film, only the sweet spot at the center of the image circle generally tends to get used, so these shots are even more precise. Just realize that there are certain older G-Claron formulas which are not the same. If the lens comes in factory shutter rather than barrel it is almost certainly intended for general photography. If barrel only, you need to ask more questions.

[Geoffrey Poulton]

Thanks everyone, and thanks Kevin for your comment about using a G Claron like any other lens, that seems to have encapsulated the whole of the answers.
It was my concern when using hyperfocal distance with a lens that I'd read needed to be stopped down to f22 to be in focus at infinity, as to whether hyperfocal distance focusing presented more of a problem for such a lens, it was this aspect that I was unsure of, but the "use it like any other lens" does put me back into an area I know and with which I can cope.

After all, I wouldn't be asking the same question my apo symmar lenses.

I have 150mm & 240mm G Clarons and a 210mm Repro Claron (he said, proudly)

[Kevin Crisp]

The repro version isn't seen that often and has less coverage. But is fine for 4X5. On some of them the glass has turned brown (tea colored) but there is a cure for that.

[Lachlan 717]

The Repro is a different beast to the G clarons. Do some research on this point.

[Dan Fromm]

It was my concern when using hyperfocal distance with a lens that I'd read needed to be stopped down to f22 to be in focus at infinity, as to whether hyperfocal distance focusing presented more of a problem for such a lens, it was this aspect that I was unsure of, but the "use it like any other lens" does put me back into an area I know and with which I can cope.

I have 150mm & 240mm G Clarons and a 210mm Repro Claron (he said, proudly)

Um, er, ah, y'r source misquoted the original. Short process lenses have to be stopped to f/22 to deliver their claimed performance. With longer ones the magic aperture is often f/32.

None of this has anything to do with focused distance. What it does have to do with is image quality off-axis, another way of saying coverage.

Re the Repro Claron, it was Schneider's answer to the Apo Artar and Apo Ronar until Schneider acquired Goerz (USA).

[Geoffrey Poulton]

Hi Kevin
I became interested in the Repro Claron after reading what Jim Galli had to say about it and the way it "divis up the contrast".
It's in a shutter at present that needs a clean and I'm looking forward to using it. It does have brownish coloured glass, but I've had it on the windowsill for parts of the Summer, I think it needs to go back on there for a while as the colour is still brownish.

[Geoffrey Poulton]

Thanks Dan,
I guess 240mm would be considered the start of longer. I've got to clean the Repro yet, it has a little something inside that would be better not being there. At present the front locking ring is very tight and I don't want to damage anything, so it's been put to one side.

The Repro is a dialyte isn't it, and for me, one of the beauties is the lack of balsam faults at anytime due there not being any. I love the Ektar 203mm and from this was tempted to look at Repro Claron - to be honest I can't wait to have it on a lensboard.

Thanks very much for showing interest and giving the information.

Geoff

[Jeff Keller]

The process lenses are designed for minimal aberrations (chromatic etc) when they are focused at shorter distances. The only thing that prevents them from focusing to infinity is your bellows length. Although their aberrations are less at the distance they were optimized for, many still have excellent performance at infinity. Similarly a lens which minimizes aberrations at infinity can still have excellent performance at distances less than infinity. For most lenses aberrations decrease as the lens is stopped down from wide open until diffraction becomes dominant.

[Kevin Crisp]

Get a black light compact florescent bulb. Home Depot has them. Take the lens cells out and put them on some crumpled aluminum foil. Give the cells exposure to the light, I use a spun aluminum reflector directed down on the glass. A week will do it. The brown will be 95% or more gone.

And if you ever start recementing lens cell, you can use the light for that. And if you get some cool black velvet paintings of pirate ships and invite people over for fondue......

[Geoffrey Poulton]

Hi Kevin

A black light sounds like a sky hook here in the UK - sort of Alice in Wonderland!! I'll see what I can locate in the UK, I think I've read your past post on that particuarly set up, but you didn't go as far as the pirate ships and fondue!

[Geoffrey Poulton]

The process lenses are designed for minimal aberrations (chromatic etc) when they are focused at shorter distances. The only thing that prevents them from focusing to infinity is your bellows length. Although their aberrations are less at the distance they were optimized for, many still have excellent performance at infinity. Similarly a lens which minimizes aberrations at infinity can still have excellent performance at distances less than infinity. For most lenses aberrations decrease as the lens is stopped down from wide open until diffraction becomes dominant.

Thanks Jeff, that's worth bearing in mind, someone on another post said that because a lens is computated for close work, it does not follow that it is poor at infinity. Thanks for this info, I'm going to remember it!

[Drew Wiley]

I have several Apo Nikkor barrel repro lenses that are simultaneously sharper at both infinity and closeup by f/111 than any official view camera lenses I own (and that includes late Nikkor M's, G-Clarons, Fuji A's). They've even sharper and better apo corrected than any offical apo enlarging lenses I own. And of course, certain Apo Ronars were famous for both closeup and infinity use, though these had less generous image circles.

[kleinbatavia]

Nothing scientific, but I've recently completed testing of a whole range of process lenses, including g-clarons. All I can say is that when stopped down, g-clarons yield incredible detail at pretty much any focal distance. You're going to be hard-pressed to find a lens that resolves more detail. Colour and contrast are good too. I can highly recommend them.

[Jim Andrada]

My second lens (bought new around 1972) for my 5 X 7 Kardan Bi was a 305 mm Repro Claron. Absolutely love it to this day. For everything near and far.

https://www.flickr.com/photos/89514126@N05/10050161335/in/photostream/

https://www.flickr.com/photos/89514126@N05/9698845504/in/photostream/

https://www.flickr.com/photos/89514126@N05/8678984258/in/photostream/

[Geoffrey Poulton]

Hi Drew
Do you mean the Nikkor M's, G-Clarons & Fuji A's are even sharper and better apo corrected than any offical apo enlarging lenses you own?

[Geoffrey Poulton]

Thanks Jim

I've come across two of these picture before when I've been looking around. I think you may have had your money's worth from your 1972 purchase of the 305mm by now - whatever you paid for it! The shutter for my Repro Clarin is being cla'd and I'm really looking forward to using it. It's hard to imagine a lens being much smaller than this as 210mm.

[ic-racer]

G Claron lenses are detailed as being capable of infinity focus when stopped down to f22.

When taking landscape images I almost invariably use forward tilt and a degree of hyperfocal distance focusing.

When the G Claron lenses (etc) are described as capable of infinity focus at f22, does this refer to the lens already having been focused out to infinity or take into account a degree of focusing employing hyperfocal distance?

Knowing the official explanation of this is probably more helpful than trying to work it out by taking a number of shots to see the effect, which is quite expensive where 5x4 film is concerned and which may not lead to a better understanding.

Extra stopping down beyond a certain point is not usually a good idea either.
I'd be grateful if anyone has any information on this or even the definitive answer.

Thanks Geoff
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.

[Drew Wiley]

Geoffrey - My Apo Nikkors (appropriately used per specific focal length) are on the ENLARGER both sharper and more "apo" than any of my official apo enlarging
lenses. On the view camera, they are equally superior to any of my official view camera lenses, optically at least. (Add a shutter, and that might be offset by
shutter vibration itself if one is forced to go to a big no.3 versus no.1, for example). But a modern plastmat G-Claron will be merely decent for enlarging - better than many older enlarging lenses, but nothing like an Apo Rodagon N. And a Nikkor M would probably be completely inappropriate on an enlarger, though its a
remarkable lens series for general shooting, provided you don't need huge image circles.

[kleinbatavia]

Quite happy with my graphic kowa and computar lenses. Also use an apo ronar 360mm, but pending develiping some sheets shot with an alternative it may have to go. Still prefer my g-clarons... They somehow enable me to create images I can't make with other lenses. Particularly in b/w.

[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_Chelsea_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!)

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[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!)

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.