Potential of (native) telephoto tilt lenses?
I posted my findings with the Canon 90TSE here but I thought it might be interesting to bring up the point on the actual e-mount forum. It has been mentioned in the past that movement range with tilt-shift optics is limited by the mirror box on DSLRs, but generally most people have accepted what is currently possible. For wider angles the needs of shift and tilt are rather moderate and they are served by the lenses were currently have - adapted or otherwise. It is only with longer lenses that tilt begins to dominate the utility factor as they are sorely limited in DOF placement. A view camera with bellows can be pretty much focal length indifferent with its movements so long as the image circle is big enough and you can still reach the front standard. With Canon the most extreme tilt will soon be the 10 degrees offered by the upcoming 90L and 135L lenses. The longer focal length tilt-shift lenses have been engineered with a "concave" tilt mechanism to prevent them from occluding early on. So without a mirror box in the way and just by using the cheapy fotga EF-E tilt adapter I was able to squeeze a full 16 degrees (lens 8 + adapter 8) of tilt from the classic 90TSE on the A7II.
I was shocked there was no visible occlusion. This is enough to get the J distance down to about 30cm. Keep in mind the old 90TSE has a 58mm filter thread (and was shot with a hood on!) whereas the new L replacements are going to be 77mm. Given the same adapter, the 135/4 promises 18mm of tilt out of the box, with probably another few millimeters could be had by shifting the lens up and tilting the camera body forward. Enough to start doing seriously (!!!) deep DOF compressed landscape work with foreground detail without stacking even at modest apertures of 5.6~11.
I am sure most of us haven't been doing landscapes on large format view cameras, but this seems significant as it is the closest (sub-medium format) equivalent to a 300mm+ lens on a 4x5 camera to date. It might take two tilt joints, or a slightly innovative mechanical design (and admittedly it is niche) but without the mirror box Sony has the potential to offer 50mm+ tilt lens options with unprecedented movements on a system camera. At least 2x the DOF placement control, ie able to frame the same landscape at less than half the tripod height with the ground still in focus. I just wonder if Sony even cares (or is aware!).