Tilt and shift lens with adaptor using XP1

Started May 15, 2013 | Discussions thread
Rod McD
Senior MemberPosts: 2,315Gear list
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Re: Lens expectations.......
In reply to baobob, May 16, 2013

Hi,

In looking at these posts, I think it's perhaps worth raising the expectations that people might have for FF lenses on these adapters.  I'll confess up front that I haven't bought my Kipon T&S adapter yet.  That's still on my radar......  However, I did use view cameras and spent far too many years of my life machining custom T&S adapters for film SLRs. I hope this helps......

People shouldn't expect FF lenses designed to cover FF to provide huge movements on APSC via T&S adapters.  You won't get as much movement as a purpose designed T&S lens like (say) a Canon or Nikon TS lens or a view camera lens.  OTOH, you will still get some very useful outcomes from them.

If you do the maths, the diameter of a lens image circle that exactly covers FF (24X36mm) is about 43mm.  Most will exceed this by only a few millimetres.  There are some that have bigger image circles, but the quality falls away outside the FF area. The illumination and resolution diminish rapidly, and they usually vignette and get soft.  Purpose designed FF TS lenses have image circles of about 60mm.  That's much larger than a 35mm/ FF lens and approaching a 645 medium format lens.  So, they offer more movement.

Shift is more demanding of image circle than tilt (unless you're doing more extreme tilting movements). The amount of correction you get will depend on the lens FL, the subject situation and how far you are away.  You'll see more effect from WA lenses.  It will also depend on the direction you're shifting.  The sensor isn't square.  If you shift parallel to the long side of the frame, you will reach the edge of the image circle more quickly than shifting parallel to the short side.  It's simply closer to the edge before you shift anywhere at all.  Your adapter may offer 15mm of mechanical shift, but your FF lens may only allow perhaps 6 - 8mm before it runs out of coverage.

Tilt (or swing when left-right) is less demanding than shift for the usual application of extending perceived DOF/sharpness in the classic landscape and still life traditions.  WA lenses have more inherent DOF and don't need as much tilt as longer lenses.  Slightly longer lenses like 35mm and 50mm lenses have less inherent DOF and will benefit more from tilt.  You will find that just a few degrees will probably gain you the benefits you're looking for in most situations.  Even 2 degrees may well be enough.  (You will need more for longer lenses and close distance applications).  And sooner or later, tilt will run you out of coverage too.....

With tilt, don't forget that not all subjects are suitable for the Scheimpflug effect.  You're not actually increasing DOF.  You're tilting the plane of focus onto the subject.  The DOF at any distance doesn't increase for any given aperture.  If you have any part of the subject outside the altered plane of focus (and not within the DOF for the distance and aperture), that part of the image will be OOF even stopped down.   And don't forget to stop down - you may be seeing at maximum aperture what happens when you set the tilt, but your lens is probably still going to be sharper stopped down two to three stops, especially if it's an older lens.  And you gain DOF.

An alternative use is subject isolation and the miniature effect.  If you tilt the lens and adjust the focusing distance appropriately, you can change the plane of focus away from much of the subject and cause only a narrow band to remain in focus - this isolates that band and with the right subject gives the miniature effect that seems to be all the rage at the moment.  (I guess it comes down to what you like.....)

I would suggest avoiding very fast lenses like (say) WA f1.4's for tilt.  It's tempting to think that this will make it easier to spot the plane of focus on the EVF.   This may be true, but the downside (apart from cost and size) is that at those fast apertures, they often have curved fields. This can make setting the degree of tilt a bit more difficult.  They're also often soft in the outer image areas at wider apertures, and it's this area that you're bringing in to your composition.  The ideal lenses are FF lenses with flat-ish fields and strong performance in the corners - look for tests indicating top performance from corner to corner right through the aperture range.  They're usually not fast.  C'est la vie.  Even f3.5 is pretty fast for a view camera!!  And at least you're not composing upside down and left right inverted under a dark hood!!

I hope this helps somebody.  Anybody.  I'd also recommend reading about the use of movements - it's very instructive.  There are whole books written on this for professionals, but IIRC, even googling 'camera movements' or 'Scheimpflug' will reach some good info.

Enjoy movements - they're great.  I can't wait to join in, but as I said to OP Baobob earlier, I've decided to await an XE/XP model with focus peaking.

Cheers, Rod

 Rod McD's gear list:Rod McD's gear list
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