210mm for 8x10"

[Corran]

eg left/right on landscape orientation being noticeably softer under magnification.

Double-check your parallelism on the camera. Oh, and make sure your lens' shutter doesn't have the little set screw causing it to sit cocked to one side. Ask me how I know about that problem...

Personally, when I shoot 8x10 I often shoot at f/45 up to f/90. Dan and others are right about diffraction, but would you rather have diffraction or limited DOF? If you want, I can send you a full-size scan of an 8x10 image shot with my 210mm f/9 Graphic Kowa stopped to f/90 (it needed it, for DOF even with movements to orient the focus plane to best fit the scene). I wouldn't hesitate to print such an image to a very large size, if I wanted to do it. As I am only wet printing right now, I made some contact prints instead.

[Tim V]

I’d love to see a scan, thanks.

I have assess to an 8x10” enlarger with ability to print up to 20x24”, so wet prints are in my future.

I think too that my tripod is letting me down and exacerbating the sharpness problems. An upgrade is in order...

[Pere Casals]

I think too that my tripod is letting me down and exacerbating the sharpness problems. An upgrade is in order...

Just attach a toy laser pointer to the front standard, and check vibration of the spot some 20m far, or 100m . You will know in what wind conditions your setup resists, and what time you have to wait from holder insertion to shutter release.

The vibration of the spot it's just the blur you would have in a long exposure, to know the induced blur at 1/100 you maye take several shots with a dslr at 1/100 to se the speed effect...


Another important thing in a tripod, after (force) inserting a holder it has to return to the same position aiming the same, if not after a tilt the change in the optical axis will move the plane of focus.

With the toy laser you can also check that the spot returns to the same place. Tripods (heads) can be a bit elastic, but they should return to the same framing after (the force) inserting the holder.

[Pere Casals]

they all show MTF @ 3, 6, and 12 cycles/mm.

Hello Dan,

The circle is specified at f/22. The graphs posted by Oren shows 40% modulation transfer in the boundary for 12 cycles/mm, so in this case the criterion should ensure an higher standard.

I guess that it should be difficult to say a precise dimension for the circle... beyond the spot in the corner perhaps it's also important the region near to the corner, so perhaps (guessing) it's also important how fast transfer is decreasing in the boundary...

Anyway having the MTF graphs the manufacturer provides very meaningful information for those concerned.

Probably (also guessing) the transfer shown in the graphs are more stable across all production, compared to the ultimate resolving power at extintion that may have more sample to sample variation...

[Drew Wiley]

Inadequate tripod heads tend to be even more of a culprit than wimpy tripods. Critical lens tests should be done on a rigid optical bench anyway, using precise vacuum film holders.

[Pere Casals]

Inadequate tripod heads tend to be even more of a culprit than wimpy tripods.

Drew, one great think of a Norma (and other cameras...) is that we can use a Tripod Head without Roll, because we can rotate the rail. This allows a lighter/cheaper steady head.

Critical lens tests should be done on a rigid optical bench anyway, using precise vacuum film holders.

This is true, but there are DIY solutions allowing some meaningful optical tests. For example by placing a x20 eyepiece in the back of the view camera we can check in "the air" the ultimate (at extintion) resolving power of a lens in different areas of the circle, (without considering alignment and focus field curvature).

[Vaughn]

Drew, one great think of a Norma (and other cameras...) is that we can use a Tripod Head without Roll, because we can rotate the rail. This allows a lighter/cheaper steady head....

I had a Deardorff Special knock-off (made in India) that had a rotating 4x5 back that served the same purpose.
If I was not so lazy, I'd use my Ries A-100 without a head (8x10 and 11x14) -- a little more work setting everything up, but should be steady. I am often on rough un-even ground setting up the camera, often with limited choices of leg placement...so the head is nice to have.

[Tim V]

I've been using a Linhof 3D Micro geared head, which seems rock solid, although just now checked the recommended max weight at it is only 10kg / 22lb. My camera only weights 4.2kg / 9.3lb, so should be adequate...

I actually also think hat the aluminium body has a bit of flex and is not so good at absorbing vibrations caused by wind and bumps. Wood or carbon fibre would be better in this regard.

With regards to 210mm lenses, I've not seen a Kowa Graphic 210mm anywhere near the $500 mark. I'll keep my eyes open...

[Pere Casals]

I had a Deardorff Special knock-off (made in India) that had a rotating 4x5 back that served the same purpose.
If I was not so lazy, I'd use my Ries A-100 without a head (8x10 and 11x14) -- a little more work setting everything up, but should be steady. I am often on rough un-even ground setting up the camera, often with limited choices of leg placement...so the head is nice to have.

I tried the rotating back of the cambo sc for roll adjustment, I found that it would require something to secure the position because when inserting the holder it can rotate a bit...

A ball head with a bulky/heavy camera it's a bit tricky to use... but I works...

[Drew Wiley]

Well, there are various past threads about going "headless". I've done it for decades with both 4x5 and 8x10; and "uneven ground" wouldn't even begin to describe the kinds of places I've routinely been. Plus to you save weight in order to increase stability, whereas trying to remove too much mass from the
camera itself sometimes does the opposite and risks instability.