4x10" (95x245mm) diagonal should be 263mm. I don't have a 150mm G-Claron but from my experience with the 210mm and 355mm ones I came to conclusion that Plasmat-type G-Clarons cover 78°; at small...
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4x10" (95x245mm) diagonal should be 263mm. I don't have a 150mm G-Claron but from my experience with the 210mm and 355mm ones I came to conclusion that Plasmat-type G-Clarons cover 78°; at small...
They work well both vertically and horizontally. They just wouldn't work OK if put completely upside down.
Dialyte process lenses don't cover, but this thread: https://www.largeformatphotography.info/forum/showthread.php?154035-Late-Wollensak-Process-Lenses-Designs-and-Specifications suggests the...
I've used #0 Seiko and older Seikosha mechanical shutters on my Mamiya TLRs. The shutters are reliable but no they are not Compur copies. The Seikos are just like the Copals, Prontors and all the...
Yes the #8 is well enough to cut the chromatic aberration (CA) off as CA is most prominent in the blue, violet and especially in the UV parts of the spectrum. In theory, an orange or a red filter...
I like the design. But I would not use a protector unless (1) I want to lower the single-cell's contrast to make it equal to the contrast of the complete double-anastigmat; or (2) the filter is...
D.R.P. is for Deutsches Reich Patent.
Funny enough, those are most probably the early (and new and exotic those days) specimens of MODERN yellow glass filters. The filter I described above was much older, coming from the pre-Protar...
~36mm? You may try a standard 35.5mm filter. Charnces are it fits.
I just realized that you probably were referring to the contrast between the different-colored subjects in the negative, not the lens contrast itself (i.e. the contrast in monochromatic subjects that...
I was visually comparing some very similar (and all excellent) lenses' out of focus rendition at f/32 using a very high quality chemically-etched ground glass. That was a tricky task; I checked and...
Yes a 'screen' means a filter. But in this case, the filter is not a clear but a yellow one; it improves single cell sharpness a lot, reducing the influence of the lens chromatic aberration.
The...
And just one last remark for those who cares about their lenses' surface spots too much:
With modern lenses, both multycoated and single coated, the image brightness range limited by the lens...
And if anybody still wants to conduct their own lens flare tests, I can recommend a reliable method with a calculatable outcome that does not requre any gear a hobbist film photographer doesn't have...
Back to the spots.... Those aren't deep enough to change a lens element shape so they can't influence the lens aberrations and its overall sharpness (actually, even the real scratches do not). Its...
The more powerful the solvent, the less times you need to wipe your lens surfaces. The more the wiping, the more the trouble and the more the risk of leaving cleaning marks.
Ether is the best...
That certainly can be done but myself, I never liked the picture made by any Tessar-type lenses' rear glass group. They are very different from the old-style cemented doublets, and the image is...
You shouldn't photograph anything for that type of test. The influence of those spots is so negligible that it is not detectable by any modern precision measuring instruments - to say nothing of an...
That's a terribly misleading papar by a very ignorant person who obviously has quite an ill self-appreciation and is eager to be a world teacher, at any cost.
Supplementary lenses are NOT filters....
And for color film, any Dagor except an MC one needs a UV-blocking filter - a real one like Wratten 2b, not a fake piece of glass with a "UV" tag. Dagor's glasses are exceptionally transparent in the...
I've just traded my 270mm Tele-Xenar for some other glass to a fellow photographer. The guy has spine problems and avoids heavy gear. Besides, he needs a back-up shutter for his 270mm Dagor, and the...
That's my main lens for 8x10" (the coverage is excessive). Stop it down at least to f/10 for the better background blur. With considerable movements, stop it at least to f/22 for better field...
Still please feel free to PM if interested in an appropriate 505 mm or 1200 mm.
(Sorry I am not sure if such a post violates the forum rules. Please remove it if it does)
Yes that's certainly subjective. Myself, I am not fond of Petzval swirly background (made up by severe vignetting in those long-barrel lenses) either. And most of the soft-focus lenses (the long...
- except the single Protar VII cells and especially the single Half-Dagor cells which a much better still; but those are way inferior in sharpness.
Yes a lot of tessar-type lenses are better than the best of plasmats in their out of focus rendition but in tessars, almost all the spherical aberration is gone when the lens is stopped down beyond...
While I agree with your general observations on the lens generations,
(1) Plasmats can easily be optimized for the background blur, too. Just no manufacturer ever bothered to design them to be as...
Symmetry has nothing to do with the out of focus rendition. The OOF rendition depends on the residual spherical aberration (SA), and SA is not dependent on symmetry at all. A prime example are those...
When there is no time to make the hood adjustment precisely, one can always make a fast rough adjustment. There will be more sideways light rays getting into the lens than with a perfect hood, but it...
That's the original Sironar, without any additional letters in the name. It's a convertible lens contemporary to (and of the same class as) the plasmat-type Convertible Schneider Symmar. The...
I think that's because in LF, the shades' shapes are dependent not only on the lens but also on the format, on the amount of tilts and shifts, on the focusing distance, and so on. So as B.S.Kumar...
One of my Schneider lenses of the plasmat type builds up quite a bit of haze on its internal glass surfaces in every several years. I've got a habit to take it apart from time to time and wipe the...
That's the point. Sadly enough, too few photographers pay the proper attention to their lens hoods, worldwide.
The 210xl's image circle is 50cm at infinity, so the total illuminated field is at...
That would be the most useful if you perform accurate tests before and after the repair, with all the conditions exactly the same.
I think a lot of people will appreciate that.
(1) I usually check the direction of any possible reflections from the surfaces I am going to paint black. If any of the reflections can go directly to the image plane, I use mat black. If not, I...
Your description most probably suggests a modified Petzval type.
But with the lens in your hands, why not to try it - at least looking at the image on the ground glass only - instead of asking...
The diaphragm position has critical influence on many aberrations, and especially on coma. And at least with simple lenses like menisci and achromats, the minimal coma is the criterion of the optimal...
(1) I am not talking about any '3d look' (which sounds quite a bit mystically, and I always strictly avoid anything non-scientific). I am talking about the out of focus background rendition in 3-D...
Or even Half-Dagors when the background is really far away (https://www.largeformatphotography.info/forum/showthread.php?163832-Protar-Lenses&p=1623018&viewfull=1#post1623018)...
My practice-based opinion is here: https://www.largeformatphotography.info/forum/showthread.php?133358-2024-quot-enlarger&p=1394698&viewfull=1#post1394698
But that's all about the purely technical...