View Full Version : F***ing Wide Open!

Arthur Nichols
8-May-2008, 18:12
OK, I highjacked the name of the thread with the many wonderful images but my intention here is something different. The thread name reflects a certain frustration with trying to shoot some longish lenses wide open.
I have been working on project that involves stopping moving water. I am using 5x7 B&W film and making some relatively big enlargements. As such I need to use a fast shutter speed (1/250 is usually the minimum). I have adapted a speed graphic focal plant shutter to use with this progect.
With regards to DOF I am shooting a horizontal plane, and I use back tilt so the DOF needs are minimal.
I have been using some Repro-Clarons (355mm and 420mm) with some some good results but have been a bit frustrated with the maximum of F/9. There are many conditions where I just don't have the available light to do what I want with the shutter speed that I need.
In an attempt to be able to photograph under a wider range of conditions I recently purchased a 360mm F/4.5 Carl Zeiss Jena Tessar. This thing is one big honker of a lens. I tried to using this wide F***ing open but I experienced substantial focus shift. The center of the image was sharp but at about 5" off the center it started to go
I couldn't get rid of the focus shift until around f/16. When I compared this to my Repro-Clarons I found that they did not exhibit this focus shift and I could actually use them open wider than the gigantic Tessar. I found this ironic.
Can anyone comment on this? 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?
Any input from the lens gurus would be appreciated.

John Berry
8-May-2008, 22:46
If you are focusing wide open and shooting wide open the only way you can have focus shift is if the standards are moving. Focus shift happens when stopping down, depending on location of apature, in some lenses. That is why you always check one last time after you stop down unless you are already familiar with the lens in question. Are you talking perhaps about curvature of field? The point of focus in a taking lens is in an arc, not flat.

Ole Tjugen
8-May-2008, 23:20
A Tessar should be reasonably flat-field, especially when using a 360mm on 5x7". There must be someting wrong with yours.

Of course the DoF is almost nonexistent...

You could try a 360mm f:5.6 Symmar - slightly smaller barrel, but an even heavier lens!

Ken Lee
9-May-2008, 02:30
How about showing us a sample image ? Since you are using back shift, could it be that some objects are outside the plane of focus anyhow, like trees ?

Tessar lenses are best in the center, until stopped-down reasonably. But that's another matter, and is different from focus-shift.

Another thought: photograph a brick wall or other flat surface, making sure the camera is lined up properly. Show us that image.

Arthur Nichols
9-May-2008, 05:30
Maybe I am using the wrong terminology. Maybe it is the curvature of the field that I should be talking about instead of focus shift. It definitely does not act like a flat field lens. I also thought that Tessars should be pretty good wide open. I will have to do some more tests, but I am confident that it has nothing to do with the rear standards or areas out of the plane of focus. I have been working on this project for some time and this is the first time that I have observed this to this degree.
The lens itself looks like it is excellent condition and it is coated. It is a fine example to the naked eye but I wonder since it is a Carl Zeiss Jena, I wonder if it was made under the iron curtain and maybe the quality control was not so good. At any rate it is somewhat disappointing. Maybe I will have to try a few more examples to get a good one. I will see about getting an image scanned and posted.

Scott Kathe
9-May-2008, 06:24
This doesn't have anything to do with the lens issue but have you thought about using a faster film?


Arthur Nichols
9-May-2008, 06:38
I am using either Tri-X or T-Max 400. I have justed started to experiment with using Acufine to try to wring out a little more film speed. I believe that I am already close to the speed limit of what I can expect from these films.
How about a 360mm F/5.6 Symmar? How would that be for shooting wide open?

22-May-2008, 06:20
These old focal plane shutters are designed for hand holding and shooting news ( like the speed graphic )- possibly under flash - or aerials ( like the Linhof FP ) ......usually on lenses that are shorter than the shutter speed . And they seem damned violent to me ! I wouldn't trust them on a tripod and 'still' shot, especially with a lens that long. SO apart from the relevant field curvature issues that John and Ole are raising, the next question is the lateral camera vibration that those shutters will generate - probably around the axis of the tripod mount. And with the long/large hourglass design of those lenses there would be greater travel and blur towards the edges. the repro clarons are quite compact ( and flat field ) so will react less to the vibration.
The communist Jena 360 f 4.5 is probably designed as some kind of 8 x 10 portrait lens designed to blow out at the edges and they saw curvature as an asset without trying to correct it ? So the result is predictable. And it must be really wide at the flanges, making it prone to shooting problems wide open - when you want the sharpness it may not have been designed for ? Faster film and smaller apertures should help. repro clarons plus flash and low shutter speed could be brilliant ?

Bruce Watson
22-May-2008, 07:08
...I recently purchased a 360mm F/4.5 Carl Zeiss Jena Tessar. This thing is one big honker of a lens. I tried to using this wide open but I experienced substantial focus shift. The center of the image was sharp but at about 5" off the center it started to go soft. I couldn't get rid of the focus shift until around f/16. ...

IMHO that's not focus shift. It's much more likely to be caused by spherical aberration. (http://en.wikipedia.org/wiki/Spherical_aberration) Older lenses are often only really sharp when used with smaller apertures in large part because the smaller apertures help mask the various aberrations.

Arthur Nichols
22-May-2008, 08:25
Interesting point about the vibrations, but after using the focal plane shutter for more than two years now I have not seen this. If my focus is good, then the negatives are dead sharp. It is amazing the tones that are revealed in moving water when it is frozen in time.
I guess what I was really hoping to get from this thread was information that would confirm if all the Tessar designs exhibit the quality or if mine is substandard. It would seem to me that a lens with coverage in the 14" range should have a greater area of sharpness in the middle wide open than 5". If someone has experienced using one of these wide open with enough sharpness in the middle to cover 5x7 I might consider to make another purchase and sell mine.
Also I wonder if there is not someone who can comment defenitely on the area of sharpness using a 360 mm Symmar at F/5.6.
I have also thought about using flash and I think it could be awesome, but it would generators, calbes lights and all kinds of paraphenalia, somewhat like a Crewdson shoot. I am not that affluent or famous yet to be able to pull that off.
I appreciate all the input.

9-Jun-2008, 06:21
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
9-Jun-2008, 07:43

" 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
9-Jun-2008, 10:52

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.



Arthur Nichols
9-Jun-2008, 11:09
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.

15-Jun-2008, 05:27
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.