Julian Loke wrote: > Well, the 2x in the Magnifier S is certainly a godsend for working with an > tilt-shift lens. Shifting, I can now manage,
I don't even see why you need the magnifier--just turn the focusing ring until the focus confirmation light comes on ;-) > but getting correct focus with tilt is still an uphill struggle. (or is > that downhill :-) Depends on which way you've tilted ... > Do you think that a higher power magnifier (e.g. A reversed EF 50mm or EF > 24mm) over the eyepiece would help? I doubt it--you really need to see most of the screen to get the tilt right. > Or perhaps your initial suggestion to put a ground glass on the focussing > rails and use an 8x loupe instead? Film rails? Surely you jest ... You wouldn't need to depend on the alignment of the focusing screen, and you could seen the entire image area at 8x, but the procedure would seem rather awkward--and you'd need to deal with getting the film in and out to allow you to focus. There's actually a much better gadget for doing this, called a ... view camera. > Or do you have special tricks to help determine tilt and focus? I wish I did ... if you read my EOSDoc tilt/shift write-up and look under "Setting the Correct Tilt," you pretty much know what I know. It's possible to calculate the required tilt and focus from a few measurements, and programs to do just that are available on Bob Wheeler's web site http://www.bobwheeler.com/photo/, but the difficulty is in getting the measurements--you need distances to two points in either rectangular or polar coordinates ... I suppose you could use the lens's distance scale and a clinometer that you rested on the hot shoe. I've thought about it but never done it. I usually set the tilt visually, using an adaptation of the technique described by Howard Bond in "Setting Up the View Camera" in the May/June 1998 issue of Photo Techniques, and summarized in my write-up. Of course a 35 mm viewfinder is quite a different animal than a 4x5 groundglass (where the loupe of your choice works quite well), and I'll concede that it's not always easy to see what is and is not in focus--especially with the TS-E 24. Unfortunately, you need to set focus at the edges rather than the center of the image area, so even a 2x loupe may not be usable. I wish Canon had an algorithm analogous to DEP that would let you set the tilt. If the TS-E lenses transmit distance information, an algorithm similar to that used on Sinar view cameras probably would work (and I'm certain that the patent has long expired). Even with some inaccuracies in the camera's data (analogous to AF inaccuracy), I'd guess that computed result usually would be better than most folks could do by eye. Sinar claimed that the computer-tethered Sinar e allowed even experienced photographers to achieve better sharpness at one to two steps wider lens openings than they could using Sinar p's, which incorporate fairly sophisticated mechanical tilt calculators. The only person I've known who had such a beast essentially confirmed the performance improvement. So few people even seem to use DEP that I'm not surprised Canon didn't implement such a scheme ... Caveat ------ One important point that I didn't cover in the write-up--if the scene is other than a flat plane (and this seem to include most), you need to pay attention to the entire scene rather than just the two points through which the plane of focus (PoF) is to pass, and attempt to cover the entire region of interest with the lens's ANGULAR DoF--and sometimes this will affect the choice of points through which to pass the POF. I made a shot some years ago on the Mendocino coast (Northern California) with a TS-E 90 overlooking a bay, with some flowers on the foreground cliff and some farm buildings on the distant shore. I put the PoF through the flowers and the distant buildings and ... the ocean below the cliff was out of focus! It's mighty unusual to see an image that's sharp in the foreground and distance and unsharp in the middle ... but I managed to do it. What I should have done was stop down (say, f/8 vs. f/5.6), and put the far focus closer to the water, allowing the angular DoF to cover the distant buildings. You can check this with a DoF preview, of course, but I find it pretty tough to critically assess sharpness looking through a 35 mm viewfinder at f/8, even with a focusing cloth. If Pop Photo have a way to do a 45x magnification in situations like these, I'd love to hear about it ;-) Sound a bit involved? It is (at least for me)! Jeff Conrad * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
