TS lenses: How does sensor size drive the weight, size, and cost of a lens?

[laroot]

I know next to nothing about designing lenses. . . . 

I shifted from film to digital with the Canon XSi.  With age and failing knees, with each passing year I’ve longed for a lighter, more compact system.  I bought the Lumix G1 when it came out, but returned it the next day because my hands were just too big to work the camera.  The NEX 6 and 7 were attractive with the corner mounted viewfinder, but I didn’t like the available lenses.  I’m about to bite the bullet and purchase *some* compact camera, but I’d like to try a tilt shift lens, and I cannot find a compact camera that supports a rational one. 

The Canon TSs work on their APS bodies, but the lenses are optimized for FF sensors, so they’re larger, heavier, and more expensive than I can accept (which is why I never bought one).  With way more with APS sensor cameras, and with the growing list of micro 4/3 cameras, I don’t understand why no one has offered a TS lens optimized for either of those smaller sensors.

That led to my present question – wouldn’t a TS lens for the smaller sensors be much lighter and less expensive?

Simplistically, it seems that the weight and volume of an equivalent lens would vary as the cube of the sensor’s side.   With a FF and a Canon APS-C cameras, the ratio is 1.6, which would seem to suggest that the lenses would vary by 4:1 (1.6^3).  Looking at Canon’s lens offerings, the EF 24-70 2.8 L is 3.5” x 4.4” at 805 grams (with 18 elements in 13 groups); the EF-S 17-55 2.8 is 3.3” x 4.4” at 645 grams (19 elements in 12 groups). 

Why aren’t there significantly greater differences in the similar lenses’ physical sizes and weights?

Thank you for any insights that you can offer.

Very respectfully,
Larry Root

[NancyP]

Concerning TS lenses in particular: These are highly specialized lenses that have low sales numbers. Users are predominantly pros or high-end amateurs who have very specific needs and expect to produce images capable of extreme enlargement. These people are using full frame cameras. Everyone else looking for novelty effects uses either a Lensbaby or a home-made tilt lens (google around). Simultaneous tilt and shift is harder for a novice DIY to put together. If you want to go the enlarger lens route, look into Zoerk adapters.

[robdickinson]

The TSE lenses work by having a huge image circle ( 67.2mm for the 24tse).



This allows the sensor/lens to be shifted around that image circle ( by max 12mm any direction).

If you were to build a crop sensor tilt shift lens you would need a smaller lens yes.  Compare the size of the 24/2.8 IS to the f3.5 24mm tse to see how much extra bulk the tilt shift adds!

Technically you should be able to design a shift adaptor for FF lenses (with longer register distances) that works fine on crop sensors. You can already do this in FF with medium format lenses (pentax especially).

I think there are mirrorless solutions here too.

But for canon to make? Unlikely as they are very expensive to engineer and used by a reasonably limited group of togs.

Have a look at the samyang 24mm tse its quite a bargain!

[laroot]

Nancy, Rob,

Thank you for your replies.

The Samyang is a nice buy, but it's a FF lens - which makes it big and heavy (but lighter than the Canon).  Big and heavy are what I was looking to avoid.  I wasn't aware of the Zork adapters - but with the 2 1/4 lens and adapter, it gets to be pretty big. 

I agree that pro users would demand a FF system, but today's compact cameras approach or exceed the IQ that pro cameras used to offer.  And while I agree that most users would not need a TS, wouldn't there be enough to support a TS optimized for a crop sensor from an aftermarket maker?  With no need for auto focus, and limiting the lens to manual aperture, the manufacturer could offer a single lens with body specific adapters -- a'la the lenses offered for manual film cameras. 

So, what I was wondering is: 

     Is there a technical reason why Canon TS wouldn't scale down if optimized for a crop sensor --
     wouldn't the required, larger image circle scale with the sensor's dimension? 

     If the lens could scale, how much would the size and weight reduce?

     Lastly, if the size and weight did significantly reduce, how much effect would that have on cost?

Very respectfully,
Larry

[laroot]

Second thoughts -- If the Samyang lenses test out similar to the Rokinon lenses, it would seem to prove that there's a market for TS lenses that do not offer the IQ that OEM lenses do.  It would be interesting to know how many of the Samyang buyers shoot them on APS-C cameras.

Larry

[NancyP]

 I just found a 50mm f/2.0 Arax TS intended for Sony NEX and M43! New, $320.00, weight 270 gm. THat just might be the ticket.
http://araxfoto.com/specials/tilt-shift-50/

I would look at cheap lenses such as the Canon nifty fifty f/1.8 II and even cheaper full frame legacy manual focus manual aperture lenses, and try to make a Tilt lens as shown in links below. Or buy a Lensbaby. These are both light weight and low cost alternatives. Or try for a used Arax / Arsat Soviet/Ukrainian TS lens. Note, you get what you pay for, so you aren't going to get the stellar performance of a Canon TS-E 24mm L II. But if you want "good enough", and lighter weight, these are some options.

http://lensbaby.com/lenses-composer-pro-edge80
http://cow.mooh.org/projects/tiltshift/
http://content.photojojo.com/diy/how-to-make-a-tilt-shift-lens/
http://petapixel.com/2012/02/15/build-a-diy-tilt-shift-lens-using-an-old-lens-shower-head-and-rubber-glove/
http://araxfoto.com/specials/tilt-shift-35/  (not as small as you wish, it's in the range of the Samyang 24mm TS)
http://araxfoto.com/specials/tilt-shift-80/  (not as small as you wish, it's in the range of the Samyang 24mm TS)

[laroot]

Thank you, Nancy.  I do appreciate your taking the time to provide those links.

I'd use the lens for landscapes rather than portraits, so 50mm would be longer than I'd want, but it is an interesting lens. I'd seen the build-a-TS-from
a-toilet-plunger concepts, but I cannot see how I'd be able to control or repeat an exposure. 

Very respectfully,
Larry

[NancyP]

The tilt effect of focus isolation (or improved focus) increases with focal length. A lot of people shoot products with medium telephoto TS lenses - the Canon 90mm TS on a full frame camera is a good example.

Get familiar with the legacy lens enthusiasts at www.mflenses.com . You might find out about a compact WA FF lens from film SLR days. Then look around on FleaBay for cheap lenses for DIY project. Or, just resign yourself to hauling a chunky lens around and get the Samyang (OK image quality when stopped down to f/8).

I have toyed with the DIY idea myself, that's why I know the sites and lenses exist. It would be cool if a M43 or NEX TS adapter could use a 20mm Voigtlander Color Scopar II, a very good FF wide angle.

[laroot]

Nancy,

Thank you for the link and the lens suggestion.  I'm at the point you suggest:  cobbling a TS adapter and a manual lens might make a functioning lens -- especially as I don't plan on huge prints.

Very respectfully,
Larry

[mcbroomf]

I enjoy using FF lenses with T/S adapters (mainly the new Kipons) on my APSc Nex bodies (5N,R,T and 6). 
18mm OM and C/Y, 21mm/3.5 OM, 25mm ZF.1.  Also the 35mm TS Canon FD, even though it's FF, is very compact.

[mcbroomf]

http://www.ebay.com/bhp/kipon-tilt-shift-adapter

[Michael N. Meyer]

I've been using one of the Kipon T/S adapters for the past year and wrote about my experience on my blog:
http://www.michaelmeyerphoto.com/daily_up/review-kipon-tilt-shift-adapter-nikon-to-nex/


Long story short: Shift works well; tilt is frustrating. It does provide a compact T/S option at the normal to short tele range but modern, well-corrected superwides that give a 24mm or wider FF equivalent can approach the size of a 24mm T/S for FF. I'm selling both the T/S adapter and NEX-7; they don't provide any added value over my other equipment, don't stack up image quality wise and are not worth the hassle. I've got other options for T/S in the studio where I most need it.

[Ajoy Roy]

The TS lenses are designed for a larger image circle. So shift of +- 10mm would require the lense to be designed for (36+20)x (24+20) = 56x44, which is the 645 format. That is why they are bulky. For APS sensor of 24x16, the lense would be designed for 44x36 still quite big. Adding tilt increases the image circle further.

What most users may like is more shift, rather than a smaller lense. So theoretically at least an APS sensor could allow more shift for the same lense. As there is an extremely low demand for TS lenses, it may not make financial sense to make a dedicated TS lense for APS or smaller format. This is more or less the situation in Super Telephoto scene. All Super Telephotos are FX, none APS. Rest assured if there is sufficient demand, then the manufacturers will jump in and supply, as is the case in Macro lenses, where there are offerings for APS sensor cameras.