F***ing Wide Open!

[BOB BERESFORD]

Realised after that while the width of the lens could be a factor, especially since you are shooting through more of it when wide open, the length of the lens encourages unsharpness once you have shutter vibration. Guys comment that they prefer compact long lenses to T type models...less blur from vibration. What camera are you using ? - and congrats on getting the Graphic shutter to 250.
Note that won't stop vibration/blur with a focal length like 360, though.

The Repro Clarons are designed to copy with flat field and quite open.
What's been said about the curvature of field and even the off axis aberration is probably the issue, and I think we can also factor in that the designers, working under East German Communism ( and don't we all love it ? ) were thinking of portraiture as a prime use. So they were glad it was blowing out the edges wide open. Why spend money correcting that ? I think that factory made more lenses with a portrait leaning ( very shallow field ) than other factories. I have a famous model ( pentacon mount ) that I can't even use on landscape at F 16 . Shallow field.
They made your lens as dual purpose - I guess - since money was short and you'd shoot portraits with it open and stop down to 32 for a landscape. Very practical.!?

The big Symmar is an all purpose lens that will certainly be better at 5.6 and can shoot to 125 with its Copal 3. I'd try the Copal and also powerful flashes on extension wires that will probably help. Easy to lengthen flash cords with basic wire.

[Paul Fitzgerald]

Arthur,

" Is there such a thing as a 360mm large F/stop lens that can actually be used wide open? Would the Xenar be a better bet or should I expect them all to behave the same?"

Yes and it's called Heliar but all of mine are pre-war, uncoated and increase contrast and sharpness stopping down to f/11. I have a new Xenar 360/4.5, it would not change anything for you. All tessars display a focus shift by f/stop and a field curvature, it's the design. That's why the phrase was "f/8 and be there".

At 20x heliars, 6 element plasmats and 4 element artars display no discernible focus shift by f/stop, any of them would work for you. For the money a Kodak Ektar 14" at f/8 would your best bet.

Have fun with it.

[Tim Deming]

Art-

Just a thought, but I have a 360mm f4.5 Heliar that gave me all sorts of trouble when trying to use it wide open. I always thought it was the lens's spherical abberations, and it wasnt until I got another heliar (480mm) which was much sharper wide open, that I realized the problem was with the lens. it turns out, someone had taken the lens apart and reversed the middle element. Since then, I've found a few other lenses (especially ones that are easily taken apart) had elements either reversed back to front, or in the wrong order.

cheers

Tim

[Arthur Nichols]

It sounds like there is at least a chance that I could find a 360mm that would be usable wide open. It doesn't look like my Tessar was ever apart but I doubt that I could tell anyways.
Art

[BOB BERESFORD]

An interesting experience from Tim - have had a technician re-do a Pentax 67 600 F4 -took ages -charged plenty - and got an element reversed!.....soft lens anyway. interesting tech info from Paul. With this situation the focus shift won't kick in but the field curvature will. however, this is leading back to the point that zeiss tessar designs were first used in press and portraiture ?.....and accordingly they were happy to drop out the background via a curved field when open ? So it's actually a design advantage there.
A large portion of pro shots on any format then would have been Portrait. Above 400 they probably assume its a copy lens for paintings etc so flatten the field more ? - like Tim's heliar. or the specialised Claron's or Apo Ronars.
Ole's suggestion of getting a used Symmar - cheap and versatile - is a good solution.

My 'lens with no depth ' is the zeiss jena Black Sonnar 180 f 2.8 with a Pentax 645 adapter on the back. It's portraits only.......which I don't do.