Used Phase One H25 Back and Sharpness

[BrianWoolf]

Within the past three months, I changed from a Betterlight 6k II scanning back to a used Phase One H25 back. An advertizing photographer had recently made the same switch and convinced me, a catalog photograher, to do it also. It was a combination of a lot of factors, mostly going from a cement floor ot a wooden floor, so it seemed like a good idea and a neccessary one. The advertizing photographer facilitated the switch, he had much better contacts than I, so it was a very good deal. I am quite pleased with the switch, the software is good and easy to use, the files look good.
   We both have one small, nagging issue. We feel that the results from the back should be ‘sharper’, when we inspect the files at 100%. Maybe the proverbial ‘tack sharp’ or a crisp file, is what we would like and often the files seem good, but just less sharp than we would like. We are using the the default on Capture One DB- (25/3). If we go up on the Capture One DB sharpening (60,80 or 125/3) or Unsharp Masking (200%, .3, 3) in photoshop, the files get ‘sharper’ but crunchier and uglier.
   I will even go a step further. I shot some tissue boxes on monday and everything looks great. Next day, I am doing christmas ornaments, and they do not look as good, not bad really, but they don’t seem to have the same quality as the previous days shoot. I refocus, and refocus, and refocus again, figureing that I missed the focus. Sometimes this does helps a little but mostly I can’t match the other day’s quality and sharpness, no matter what I do. So I do wonder if I am just going a little crazy, how can a back work well one day and not so well the following day.

   Are there better sharpening solutions for this back, either in Capture One DB or outside it?
   Does anyone else have issues like this, with the H25 back?

We are using the H25 back on a Hasselblad and a Sinar P2 with the Phase One sliding adaptor with Apo-Sironar 150mm and 180mm lenses.
   I recently had a problem with the focus and fine detail rendering of a Ferragamo tie, which I will bring up in another post.
Brian

[Bernd B.]

We are using the H25 back on a Hasselblad and a Sinar P2 with the Phase One sliding adaptor with Apo-Sironar 150mm and 180mm lenses.
[a href=\"index.php?act=findpost&pid=136206\"][{POST_SNAPBACK}][/a]

I think the two lenses are made for 4x5 inch sheet film and are not good enough for a 36x48mm digital back. You will have to buy at least one Schneider Apo Digitar. If your budget is limited you could buy an older Apo Ronar.

[psp]

I think the two lenses are made for 4x5 inch sheet film and are not good enough for a 36x48mm digital back. You will have to buy at least one Schneider Apo Digitar. If your budget is limited you could buy an older Apo Ronar.
[a href=\"index.php?act=findpost&pid=136214\"][{POST_SNAPBACK}][/a]

Agreed - the lenses you have are not recommended for digital. You will see a major difference.

[DavidP]

I have had the same experience being disapointed with the sharpness with the traditional view lenses. If you try shooting with something like the 120 Makro Planar on a Hasselblad you will know it is not the back.
Something else I have noticed, things get even worse when stopping down to f22 or more.

[psp]

Something else I have noticed, things get even worse when stopping down to f22 or more.
[a href=\"index.php?act=findpost&pid=136230\"][{POST_SNAPBACK}][/a]

Yes - that's something more apparent to digital than film. Most lenses have optimum sharpness/performance at f8-f11, and as a general rule, one should not go beyond f16.


Cheers!

[psp]

For a more detailed explanation:

http://www.schneideroptics.com/pdfs/Digitar.pdf

[Mark_Tuttle]

Yes - that's something more apparent to digital than film. Most lenses have optimum sharpness/performance at f8-f11, and as a general rule, one should not go beyond f16.
Cheers!
[a href=\"index.php?act=findpost&pid=136246\"][{POST_SNAPBACK}][/a]

That is the ironic thing about the whole situation.  We go to larger digital sensors for sharpness and so buy the lenses made for digital to provide the best the sensor can offer, then learn that we have to use F8 or F11 to get the sharpest image but end up getting less depth of field.  F16 is fine with sharpening.

Of course it isn't mentioned that the smaller the photosites are the smaller the circle of confusion is and so the depth of field seems less than we were used to when shooting 4x5 film.  

Yes, we are looking at greater magnification but there are other factors we need to consider these days when previsualizing.

[psp]

That is the ironic thing about the whole situation.  We go to larger digital sensors for sharpness and so buy the lenses made for digital to provide the best the sensor can offer, then learn that we have to use F8 or F11 to get the sharpest image but end up getting less depth of field.  F16 is fine with sharpening.

Of course it isn't mentioned that the smaller the photosites are the smaller the circle of confusion is and so the depth of field seems less than we were used to when shooting 4x5 film. 

Yes, we are looking at greater magnification but there are other factors we need to consider these days when previsualizing.
[a href=\"index.php?act=findpost&pid=136287\"][{POST_SNAPBACK}][/a]

In my experience, sharpness and depth of field are somewhat subjective. Comparing a MF tranny on a light table to a digital capture on a 30" monitor are worlds apart. Even film lenses were/are best at f8-11, we just never really held it up to the microscope like we can with digital....

best....