Tessar question

[Randy]

I have a B&L 11X14 1C Tessar f/4.5 that I play with on my 8X10 - a pretty large and heavy lens. When focusing with the loupe at wide open it is not sharp. If I close down to f/16 or so, it is sharp. Just wondering if this is expected results from old Tessars? I would like to have to option of shooting wide open but it is just to soft, even in the center. I am wondering if the element spacing could be off. Could the cells be screwed in to far or not far enough? How would I determine the correct distance? Thoughts?

[Ian Greenhalgh]

4.5 Tessars can be soft wide open, I have a Kodak Anastigmat 4.5 that is a Tessar and it is soft wide open, it's probably the softest Tessar type I've shot, even stopped down.

[John Kasaian]

Old tessars are like that. Some tessars that are noted to be "sharp" wide open are the Commercial Ektars (f/6.3)and Nikkor M (f/9)
At least thats my story and I'm sticking to it

[Ian Greenhalgh]

The 6.3 Tessars and the Nikon-M are both examples of reducing the maximum aperture and also ensuring the corrections were of the highest order, they outperform faster 3.5 and 4.5 Tessars. CZJ did the same with the 8/270 Tessar and they say that is the best Tessar ever made.

I have a Schneider Linhof Selected Xenar 3.5/105, it's a very nice lens but isn't very sharp at all wide open, it actually makes it more useful as it can serve double duty as a portrait lens wide open then a good general purpose lens stopped down.

[genotypewriter]

I have a B&L 11X14 1C Tessar f/4.5 that I play with on my 8X10 - a pretty large and heavy lens. When focusing with the loupe at wide open it is not sharp. If I close down to f/16 or so, it is sharp. Just wondering if this is expected results from old Tessars? I would like to have to option of shooting wide open but it is just to soft, even in the center. I am wondering if the element spacing could be off. Could the cells be screwed in to far or not far enough? How would I determine the correct distance? Thoughts?

How close are you focusing, Randy? I have a few Tessars and with my Fujinon 300 5.6 I've noticed that subjects focused far away are significantly sharper than when the lens is focused near-by (portrait distances). In the latter cases the lack of sharpness is fairly noticeable even when looking at a bare 8x10 transparency.

If you're really worried about cells in the wrong distance, why not experiment a bit by unscrewing them, etc. and checking just for the fun of it

[Randy]

I was focusing on my girlfriend the other day. She was about 5 meters distance. I have used the lens only a few times and they all have been fairly close. I have not played with distant subjects yet. I have only one other Tessar to compare it to - a 180mm Congo, which seems to be very sharp in comparison. I will play with cell spacing soon. I have not taken the lens apart as it is kind of tight and I don't want to mess up any threads.

[Armin Seeholzer]

Hi Randy

Maybe you got a misused one. I have 3 LF Tessars which the oldest is from around 1949 Zeiss 250mm f3.5, one is from around 1982 f 4.5 300mm, 1960 Xenar f 4.5 480mm all of them get sharp in the center at 1 f stop closed and over the whole field of view at f 8/11 and the bokeh is a dream wide open down to f 16.

Cheers Armin

[Randy]

Armin, this is a B&L with 1903 stamped on the barrel. Not sure if that is the manufacturing date. No doubt it has been banged once or twice, especially on the lens hood, which I can't remove. I may try to get it apart and make sure an element hasn't been jarred out of alignment. Like you, my other Tessar (Congo 180mm) is very sharp in the center and I just love the bokeh. This one does get nice and sharp(ish) at 16-22, so it is very usable.
As I am focusing - moving critically between out and in focus, it is just difficult to tell when it is in focus because in focus is not much different than slightly out of focus, when focusing at f/4.5. I may just have to live with it.

[Randy]

Well, after several dismantlement's, putting it back together and trying it on the camera in between, I think I finally git it right. Problem with these old lenses, I am learning, is the threads don't hold up very well. As my Dad often says - "Maintenance begets maintenance". A previous owner must have gotten a cell cross-threaded. I almost had a pricey paperweight. Amazing how just a fraction of mm in misalignment can make such a big difference.
Image now is softly sharp at f4.5 and very sharp at f/16. Was getting dark so will shoot some tomorrow.
What are some options on a lens when the threads are shot / almost shot? I was almost to the point of filing them off and slipping the lens cell in and just putting a couple spots of glue to hold it.

[genotypewriter]

I was focusing on my girlfriend the other day. She was about 5 meters distance.

Sounds like you're a true large format shooter

What are some options on a lens when the threads are shot / almost shot? I was almost to the point of filing them off and slipping the lens cell in and just putting a couple spots of glue to hold it.

Yeah that should do it... but it sounds like a pretty beat-up lens. I have some very old lenses (Tessars too) and they're in much better shape, have to say.