I had exactly the same problem. I collimated my lens as well. It only gave sharp results at about f16, but f8 or f5.6? no... only sharp center, the rest was poor.
Are you sure about the Selfix 820? I ask because I've never got a satisfactorily sharp shot with mine, even on tripod. The lens is in collimation and the focusing scale seems to be correct. See http://www.filmstillphotography.com/ensign-selfix-820.html for a review that agrees with me. It has one thing wrong, the lens is 105/3.8 Xpres in Epsilon shutter. The shutter is supposed to be flaky. Mine has behave well, so far but with very little use. Overall, a Century Graphic is a better tool, and many of them have, unlike the Selfix 820, a coupled rangefinder.
It is my understanding, that in the same way that a lens where the focal length is roughly equivalent to the diagonal of the film is easiest and cheapest to design, it also has a focus distance that it “likes” the best, that also corresponds with a multiple the focal length.
I don’t know the reason for this, or can give you the math, but that’s what I read “somewhere”.
I have had some 120 folder cameras: A nettar 6x6, Agfa Record III with solinar, Ensign Selfix 820. The only one to give me really sharp results is the one I kept: The Zenobia Folder with Neo-Hesper lens.
Probably due to this camera having actual film rails, and the smaller 6x4.5 negative.
It wouldn't be strange though, since you are very slightly adjusting focal length when focusing.It is a rule of thumb, but it is not that that accurate.
It would really make little sense to design for infinity since very few people actually take photos at that range and even those that do only some of the time.fwiw the point of best image quality on a front cell tessar is up to the designer. I have heard that some were designed for infinity, some for about 8 ft (the portrait length?) but the most important thing is that it is probably not consistent between cameras.
Two more photograhs with the Zeiss Ikon Super Ikonta III 531/16 - Novar Anastigmat f/3.5 75mm (which I bought for about 120,- EURO two years ago)
It would really make little sense to design for infinity since very few people actually take photos at that range and even those that do only some of the time.
Remember these where consumer cameras back in the day. Most photos are of people or objects in the interaction range.
I think the internal justification in the argument for infinity as benchmark, that has spread as the common explanation, is that it's supposedly what you calibrate the lens for easily with a collimated source.
Infinity is however a rather poor mark to use as reference, as it's pretty forgiving.
Of course you should be able to hit it reasonably well, but it's not as hard as say nailing three meters dead on.
Second that after shooting dozens rolls of 120 film with various Isoletts since the 1990s. Currently have four of them, with one converted to a pinhole camera.Super Isolette is the sharpest of all my folders.
It’s hard to say anything definite from such small scans, but it does look good and contrasty.Two more photograhs with the Zeiss Ikon Super Ikonta III 531/16 - Novar Anastigmat f/3.5 75mm (which I bought for about 120,- EURO two years ago)
View attachment 268272 View attachment 268273
But how does it compare to the 3.5 at various apertures. Including completely open?I currently own several f/3.5 Novars. I've owned and used both the f/4.5 and f/6.3 versions. I always shoot stopped down to f/8 or lower and can't see any difference between the 3.5 and 4.5 versions. The f/6.3 version had noticeable vignetting at the edge of the field and I sold it right away. I can heartily recommend the f/4.5s. They're usually fitted to Nettar bodies which are virtually identical to the Ikonta bodies. A Nettar with a 4.5 will give you great bang for the buck.
Sorry, I can't answer that as I always use f/8 or smaller. Many years ago I ran experiments with the 3.5 version and the photos wide open were soft and had corner distortion; by f/8 the images were nice and sharp. At f/16 they're as good as a Tessar and at f/32 they are still wonderful.But how does it compare to the 3.5 at various apertures. Including completely open?
Me too. That’s what I meant. Hard pressed I’ll go down to 5.6.Sorry, I can't answer that as I always use f/8 or smaller. Many years ago I ran experiments with the 3.5 version and the photos wide open were soft and had corner distortion; by f/8 the images were nice and sharp. At f/16 they're as good as a Tessar and at f/32 they are still wonderful.
Not that I could see. The condition of the lens and camera are more important than anything else.Me too. That’s what I meant. Hard pressed I’ll go down to 5.6.
Are there differences between the 3.5 and 4.5 version at optimal apertures. IE 8 to 22?
Only if someone tampered with it along the way.Not just the condition but the calibration. Most cameras that were made 50 years ago's infinity focus position is wrong if not set recently.
Maybe there were lots of bad repairmen in the past. My statement is based on some observations I took with a recently acquired autocollimator from a forum member. After reading this thread I have been checking my cameras for focus accuracy at infinity, using the reflection of a collimated target off real loaded film (following these instructions: https://learncamerarepair.com/downloads/pdf/NatCam-Auto-Collimators.pdf) and have been blown away by just how bad most of them are. They were so bad that it made me wonder if the autocollimator's calibration was off, but I tested it with a mirror and by testing the infinity focus of a lens in my DSLR (with a known good infinity, tested by taking a picture of a building a mile away right before the test), and that combination tested near perfectly. In comparison, my TLRs and folding cameras have been stupendously bad, returning focus error at infinity of an actual focal point around 30-50m. Why haven't I noticed this before? Well, infinity is well within the hyperfocal range at 50meters/f11 and I am guilty of racking the focus all the way to infinity rather than thinking about hyperfocal range most of the time. One of the more interesting tests was that several of the lenses I sing the most praise of on this forum (Hasselblad 60mm, Mamiya TLR 80mm) "just so happen" to have the best infinity calibration, and the lenses I have often said I "got a bad copy of" (Mamiya TLR 65mm, Perkeo II color skopar) are the most out of calibration...
It would really make little sense to design for infinity since very few people actually take photos at that range and even those that do only some of the time.
Remember these where consumer cameras back in the day. Most photos are of people or objects in the interaction range.
I think the internal justification in the argument for infinity as benchmark, that has spread as the common explanation, is that it's supposedly what you calibrate the lens for easily with a collimated source.
Infinity is however a rather poor mark to use as reference, as it's pretty forgiving.
Of course you should be able to hit it reasonably well, but it's not as hard as say nailing three meters dead on.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?