Wide aperture performance of 110mm to 120mm lenses

[Bob Salomon]

How do you think the rear filter threads got there, by accident?

No, they are the threads for the retaining rings for the Les. AGAIN, placing a filter behind the lens ALWAYS degrades the image. Placing anything behind the lenswill always create a focus shift. All lenses that have been designed for a filter inside the lens or with the lens are always manufactured and sold with at least one filter installed in or on the lens.

The only possible exception to this were the Rodenstock HR Digital lenses which required an optional corrector glass behind the Lens to be used if the lens was to be used with film rather then digital. The reason for this was that the cover glass over the digital sensor was part of the lens design. A few universities bought these lenseswith the corrector plate for film use. But the sale of corrector plates was so minimal that they were discontinued after a year or so.

[dave_whatever]

No, they are the threads for the retaining rings for the Les.

The rear retainer may also use that thread (I will have to check my copy of the lens at home) but Schneider's own literature says the thread on the back of the 110XL is a "Rear screw-in thread for a further filter". They designed the lens to take a filter, it is even the correct standard 52mm size and 0.75 pitch.

https://www.schneideroptics.com/pdfs...LensCharts.pdf

Nobody is arguing that using a rear filter won't theoretically impact on optical performance. The fact remains Schneider designed the lens to give you the option of using a rear filter.

[Bernice Loui]

Matter of individual preference, no?

Being one who has tried ALL of the current modern plasmats on the market in the past (Nikkor, Rodenstock, Schneider, Fujinon and others) they do have a specific image quality and it is a matter of individual preference as to what is ideal for the image maker. Nothing more, nothing less.

There are four lens formulations that appeal to me in these focal lengths Kodak Ektar, Schneider Xenar, Dagor, Artar. None deliver the modern high contrast overly etched look some are interested in. There are many other factors than simple "sharpness, contrast" and all of those metrics overly abused these days as to what constitutes the best-ideal lens. So there ya go.

Flawed is much a matter of individual opinion. Get the optics, try them out and use what is preferred plain and simple.



Bernice

Bernice, the only problem with Christopher Perez's 210mm lens tests you linked to is he appears to be testing them with a 5x4 camera/enlarger and these are lenses designed for normal use on 7x5 cameras. It's also a pity a more modern plasmat like a 210mm Symmar S wasn't included.

In the context of this thread where the OP is shooting 5x4 what's relevant is Perez shows 210mm Tessar & type lenses are excellent performers for the format, he states the 210mm f6.1 Xenar is the sharpest of the lenses he tested. But of course he's only tested the central parts of the image circle where we'd expect better sharpness.

Ian

[Bernice Loui]

Using a filter on the rear impacts the image no more than using a filter in the front. Filter in the front has a different set of problems than filter in the rear.

After ownership of this Schneider 110mm XL for nearly two decades and use a filter on the rear element (and filter in the front with 67mm-72mm step ring or Sinar 103mm glass filter system) over that course of ownership, curious to read using a filter in the rear cannot be done and affects image quality..

Focus shift due to filter on the rear element is irrelevant as the image to be created will be focused on the ground glass with the rear filter in place. This accounts and compensates for the slight focus shift due to adding a filter on the rear element.


Why have some of the relies become SO combative and trolling for arguments that are not fact?


Bernice

The rear retainer may also use that thread (I will have to check my copy of the lens at home) but Schneider's own literature says the thread on the back of the 110XL is a "Rear screw-in thread for a further filter". They designed the lens to take a filter, it is even the correct standard 52mm size and 0.75 pitch.

https://www.schneideroptics.com/pdfs...LensCharts.pdf

Nobody is arguing that using a rear filter won't theoretically impact on optical performance. The fact remains Schneider designed the lens to give you the option of using a rear filter.

[Bob Salomon]

Using a filter on the rear impacts the image no more than using a filter in the front. Filter in the front has a different set of problems than filter in the rear.

After ownership of this Schneider 110mm XL for nearly two decades and use a filter on the rear element (and filter in the front with 67mm-72mm step ring or Sinar 103mm glass filter system) over that course of ownership, curious to read using a filter in the rear cannot be done and affects image quality..

Focus shift due to filter on the rear element is irrelevant as the image to be created will be focused on the ground glass with the rear filter in place. This accounts and compensates for the slight focus shift due to adding a filter on the rear element.


Why have some of the relies become SO combative and trolling for arguments that are not fact?


Bernice

When a filter is used in back, besides creating a focus shift, any dust, fingerprints, smudges, etc. that are on that filter will effect the image as those defects were not part of the lens itself.

[dave_whatever]

The main theoretical problem with rear filters on a wideangle lens is the focus shift is not constant over the image circle, as light passing from the lens to the edges of the image circle do so at a progressively steeper angle to the perpendicular. Hence a 2mm thick filter causing x focus shift on axis will cause a worse focus shift at the edge of the film area because the light might at that angle be passing through say 2.5 or more of glass, since light there has passed through a 2mm filter at a steep angle.

Clearly though this effect could well be more than masked by other effects, tilt, depth of field etc, which folk's real world experience above attests to.

[Bernice Loui]

Bob,

Why are you so combative on this..

Any focus shift is compensated for when the rear filter is on the rear element and the projected image focused on the ground glass. If this is not correct, the laws of Physics has changed. Small to moderate amounts of dust affects the image a lot less than most would imagine. Simply calculate the actual area of the dust particle relative to optics area. It is no worst then bubbles in the glass and such. Fingerprint-smudge can happen on ANY optical surface. If the smudge, finger print or similar covers a large enough optical area, it will affect image quality.

Losing face due to being factually incorrect is not the end of the world. Don't be learning resistant. Learning is how one grows their intellect and this is a matter of intellectual honesty, intellectual integrity.


Bernice

When a filter is used in back, besides creating a focus shift, any dust, fingerprints, smudges, etc. that are on that filter will effect the image as those defects were not part of the lens itself.

[IanG]

Matter of individual preference, no?

Being one who has tried ALL of the current modern plasmats on the market in the past (Nikkor, Rodenstock, Schneider, Fujinon and others) they do have a specific image quality and it is a matter of individual preference as to what is ideal for the image maker. Nothing more, nothing less.

There are four lens formulations that appeal to me in these focal lengths Kodak Ektar, Schneider Xenar, Dagor, Artar. None deliver the modern high contrast overly etched look some are interested in. There are many other factors than simple "sharpness, contrast" and all of those metrics overly abused these days as to what constitutes the best-ideal lens. So there ya go.

Flawed is much a matter of individual opinion. Get the optics, try them out and use what is preferred plain and simple.

Bernice

When I said flawed I qualified why - the tests Perez made were based on 5x4 with no movements with lenses designed for 7x5 and some small amount of movements so not being used to their full capability.

What Perez did show was there was little to choose from other than greater edge/corner softness with the Geronar at wider apertures when these lenses are used with a 5x4 camera. As it happens I do use Tessars, Xenars and Ektars (dialyte - so in that respect the same as an Artar) and Dagors as well as modern Plasmats. My point really is with shorter FL lenses of these same types on a 5x4 camera you will see greater differences particularly at wider apertures, and the same would be true with the lenses Perez tested if he'd tested with a 7x5 camera.

The point we are both making is these older lenses Tessar, Xenar etc are very capable lenses my only caveat is coated versions. I used a 203mm f7.7 Ektar (Compr #1 - a very late US version) on a 6x7 MF camera a few weeks ago and the sharpness is outstanding, Do I prefer it to my 210mm f5.6 Symmar S or 210mm f6.3Osaka Commercial, not really except it's small and light, a touch harder to focus but for close up work will out perform a Tessar or Plasmat.

Ian

[Bob Salomon]

Bob,

Why are you so combative on this..

Any focus shift is compensated for when the rear filter is on the rear element and the projected image focused on the ground glass. If this is not correct, the laws of Physics has changed. Small to moderate amounts of dust affects the image a lot less than most would imagine. Simply calculate the actual area of the dust particle relative to optics area. It is no worst then bubbles in the glass and such. Fingerprint-smudge can happen on ANY optical surface. If the smudge, finger print or similar covers a large enough optical area, it will affect image quality.

Losing face due to being factually incorrect is not the end of the world. Don't be learning resistant. Learning is how one grows their intellect and this is a matter of intellectual honesty, intellectual integrity.


Bernice

But it does affect me he image, as you just admitted. Filters belong in front for best results from the lens. Assuming that you are using high quality filters to begin with.