i am using the e75 together with a siimilar camera than the alpa12swa. its a gottschalt camera together with a set of sinar rodenstock HR and digital optics starting with 28mm.
works very good so far.
the 28hr is more expansive, but:
it allows you movements up or sidewards of app. 12mm,- so the image circle of the optic is somehow bigger than the 24xl.
it has less fall-off so you can work without centerfilter, with the 24xk you should use a cf.
the 28hr is sharp till the edges even at f4, the 24xl wants too be stopped down 2stops for best performance.
the color casts should not have effect if you work in b+w,
i think they are not strong enough to change the luminance significant.
some additional advices for testing, sure there are many more....
shoot some images where saturated blue sky is in the image to see cf issues.
shoot one image with a neutral grey wall to see color shifts.
take care you have enough time to learn how to handle the backs, esp. the conversions,- otherwise it might be difficult to have anything said by your test.
with phase you should use in any case their LCC method. same with sinar and leaf with white references. try with sinar for on location shots the brumbaer software also.
make sure that you will get the SAME back which you tested if you decide to buy it.
the things are not going all about quality, so if one back is good does not mean that the next is also the same. esp. with the cf issue you may have luck with one back but you might not have luck with another for system immanent sensor tolerances.
I apologize if this is drifting off topic......
The 28HR from your description sounds like fascinating lens........I can't seem to find the right site for lens data. Do you have a link?
(BTW....your observations and remarks are costing alot shooters alot of money )
I have the 24xl...shooting on an A22 back. Center filter is not necessarily required when you use the Custom Gain Adjuster to remove color casts. There is a feature in the Leaf Custom Gain Adjuster utility that allows you to adjust for lens fall off from 0 to 100% in addition to correcting color casts as well as correcting CF issue. I recently did specific CF tests with an A75 using Schneider 24xl and the 35xl lenses. The easiest way to reveal the CF issue is to shoot a reference
file using white translucent acrylic (LCC method) with zero to maximum shifts applied to the lens being tested. It is a worth while test to confirm that the back manufacturer has a solution to address the CF issue and color cast issue (phase,sinar, & leaf..I think Hassy also has a solution for CC issue) before signing the big check and marrying the back manufacturer.
Currently, I am using a Leaf back and there are two Leaf solutions that address the CF issue that is evident in the Dalsa chips. If you use a non shifting lens camera and show no color casts, the Wide Angle Convertor utility will remove a CF issue (if present). If you use shifting lenses, the Custom Gain Adjuster utility is a better choice since it will remove both the CF and a color cast (if present).
Currently, these utilities are applied to raw mos files prior to processing (giving you the option to select Raw processor software of your choice). It is a workaround that adds time to post.....but since I am not processing the quantity of files as a fashion shooter might its not a big deal.
It would be nicer if the software worked more efficiently......but I am very happy with the hardware and the files that are produced by the Leaf software for my application.
Rainer, your custom gottshalt with a sliding back sounds like it is a wonderful camera for architectural or landscape shooting and it seems like it works very well with the sinar back and its interchangable plates.
A couple of questions if you don't mind.
Is it possible to use other backs that do not have an interchangable mounting and still be able to use a sliding back and be able to focus a Schneider 24xl @ infinity?
What is the longest exposure the e75 allows?
How are you able to compose axial elevation symmetrical shots without a geared movements?
If I understood your previous posts correctly, the gottshalt front panel moves in all directions and is locked by one knob. How do you make micro adjustments without x and y gear movements?
I know the answer........ you are a buddhist zen monk but I thought I would ask anyway!