Digaron-S HR 4/60 mm on 33x44 sensor like Fuji GFX100, hasselblad 907x100S, XD2

[stevev]

Here is an example of the Rodenstock (Sinar) Digaron-S HR 60mm/F4, shot with 3 rows and 3 columns on a Cambo Actus G, stitched together. So 20mm shift left and right, 15mm rear fall and 12mm rear rise on a 36mm wide x 24mm tall sensor, making the coverage 76mm wide by 51mm tall.

I have tried my best to place the stitched image against image circles of 70mm, 80mm and 90mm to give an indication of the circle of illumination and the location of the hard stop, if that is the correct term for it.

The first image shows the light falloff uncorrected.

The second image shows 100% vignette correction in Lightroom, to better show where the hard stop is.

My conclusions are that light falloff begins gently after 70mm, and significantly after 80mm, and that the hard stop is at around 90mm.

 

[Paul Spinnler]

Yes, this is what I saw as well, I see the hard border after 15mm rise on a full-frame chip. As said, the inspec 60 4.0 should be a very interesting option on a bellows cam or mounted via a third party service, e.g. SK Grimes in combination with an ES back.

Also if stitching is not a prriority and moderate shfit ways are used, this lens is also a good option for full frame, ie 10mm rise for example in landscape.

Most likely, for critical IQ4 purposes, one should be fine with 5mm-10mm rise, but not more, rest would be for sky etc. - so the 70 HR as many times concluded may be the best solution for full frame backs while the 60 HR is good for crop, and by extension also the inspec lens.

Will validate definition though with rise, maybe its tack sharp till shortly before the black border.

Other issue of course is that there are no lens correction profiles available that I am aware of.

This alone is a biggie for some applications like architectural photography of course.

 

[Alkibiades]

A 15mm shift on an IQ4 150, in landscape orientation, needs an image circle of 88mm. That is 18mm larger than the official 70mm circle.

If image quality is good that far out in the shifted zone, then that is an astonishing performance. Why would Rodenstock spec it as a 70mm circle when it's actually a lot bigger?

this is really a good point.Whole Rodenstock Digaron-S line from 23 till 100 mm should have only 70 mm image circle, but in fact all of these lenses have bigger real image circle and very different image circle. the smallest have 23 hr and 28 Hr, than it grows with 35 HR, grows again with 60 hr and will be much, much bigger with 100 HR. Only the longest : Digaron-S 180 Hr got theoretical bigger image circle of 80 mm- but it is also much bigger in real.
I work much with the 23 hr that have the smallest image circle and get about 11-12 mm rise on 33x44 sensor. with 35 hr about 16-18 mm.
With the 60 HR the details even in dark edges till the total black are still very good. This is much better than on symmetrical lenses wher the decrease is extrem.
Even Cambo tested the 100 HR, they could not believe that the real image circle is so much bigger, and it is indeed.
Rondenstock stays here extremly conservative, maybe there was not a big need for it becouse when the big sensors come out rodenstock began to make lenses with bigger image circle. The whole Digaron-S line was not in focus any more except the 23 hr for that there is still not alternative with a bigger image circle, the big sensors with 60-80 MP and than 100 and 150 MP were the profesional standart. But now the small 33x44 mm chips with the much more atraktive price, great quality and modern BIS technology seems to be the future products for the most users. So the Digaron-S line is so actuall as never before, the 100 MP needs extremy sharp lenses to show their potential.