Pentax 645 33-55 + Zoerk PSA + Canon 5D

[aoluain]

December 10, 2008 at 8:53 am

Anyone seriously interested in SHIFT lenses for Architecture?

After spending a lot of time researching Tilt and Shift lenses I happened across an
alternative using medium format lenses and a shift adapter.

On my travels through cyberspace in search of a solution I learned a lot regarding
The advantages and disadvantages of basically three systems.
1. Standard Canon shift lenses,
2. Shift lenses from other manufacturers mounted via an adapter,
3. Medium format lenses mounted with a shift adapter.

I did some research initially on the Canon TSE 24mm L shift lens and after reading reviews and the Shift concept including the mechanics of how it works decided against the Canon. I then happened across the following site testing 3 different lenses from Nikon, Olympus and Contax/Zeiss . . .

http://www.16-9.net/lens_tests/35mm_shift/35mm_test1.html

On this site they compare 3 35mm shift lenses on a Canon 5D. I was really tempted
To buy a similar 35mm shift lens after reading this review but 35mm is just not wide enough for interiors.

The last paragraph of the 35mm test above left a little question mark with me . . .

“A question now arises, however, as to how the biggest fish in the little pond compares to the biggest fish in a bigger pond: will the CZ35 PC outperform the finest medium format ultra wide: the tragically discontinued Pentax 645 FA 35mm? We’ll be finding out in the next few weeks.”

So I started checking out Pentax 645 35mm lenses and how to get them to shift and happened across a device called a Shift adapter. This took me in another direction and a lot of surfing until I landed here . . .

http://www.zoerk.com/pages/p_psa.htm

The weak point regarding Canon’s shift lenses and most other 35mm format shift lenses is the image circles they throw. When we look through out cameras we are fooled in some way thinking of a rectangle but the lens covers a greater area than we see through the cameras viewfinder.
A lenses image circle has a SWEET spot which is obviously in the centre and the closer we go to the edges the more distortion and aberration we get, so when a shift lens is SHIFTED it is essentially moving the RECTANGLE away from the centre towards the undesired areas of the lens. The amount of shift on the standard Canon is only about 11mm.
Medium format lenses throw a bigger image circle so the sweet spot technically is bigger which enables a bigger amount of movement to take place before the weaker edges of the lens comes into play. The amount of shift is far greater on this system at 20mm against any other system.

Here is more on Image circles . . . http://www.stitchpix.com/image_circles.html
So I decided to bite the bullet and invest in a Zoerk Panorama Shift Adapter and a Pentax 645 lens. Especially the 35mm FA version which is reputed to be the best 35mm Medium format lens out there. I have read that some users rate as rivalling 35mm format 35mm lenses!

http://www.16-9.net/lens_tests/pentax645_fa35mm.html

Anyway I couldn’t source one as they are like hens teeth at this stage so I opted for the 33-55 lens for a slightly wider view.

Below is a series of pics of how the system works . . . more at a later stage!

My first outing with the new system was a few weeks ago and I was highly impressed . . . no cenverging angles.

The one drawback with using this system is it is all manual, manual focusing, manual aperture and stop down metering.
The syatem also allows you to creat a panorama or a series of 3 pics to creat a wider view which is equavilent to about 19mm,
I will post a sample soon. The system also allows you to creat a 3:1 panorama which I tested and is very easy and Photoshop
blends in effortless time.

So what more can I say it is a fab system and fun to use, for people used only to AUTO everything it is a bit daunting but
in general using other manufacturers lenses on a different body is not that bad depending on the application of course.

[jb7]

December 10, 2008 at 10:29 am

You mention that 35mm is not wide enough for interiors-
and I’d have to agree- in general-

The difficulty with the shift adapter is the limitation on shorter focal lengths,
but it works just fine for longer lengths-
making it really useful for pack shots, macro, or anything where the perspective needs to be controlled-

The stitching thing will allow you to make bigger pictures- more pixels-
but at the cost of removing the one big advantage of shift lenses-
perspective control-

The lens effectively returns to its original condition, and works axially-

Regarding the quality of individual optics,
I’m not acquainted with those lenses,
but mf lenses can be very good, as you say-

If your goal is ultimate quality,
I’d be tempted to listen to PTB’s discourse on the merits of primes-
as you yourself mentioned earlier in your article-

I’ve seen pictures from the Nikkor 24mm t/s-
and it looks like the best example I’ve seen in that range-

Good to get away from the fixed axis though-
looks like you’ll have some fun with that-

j

[aoluain]

December 10, 2008 at 2:18 pm

Yea i have read a good few reviews regarding the other manufacturers shift lenses,
but the trouble still lies in the potential deterioration of the quality the more the lens
is shifted to the edges of the lens.

I think most of these lenses only start performing at about F8 or F11.

I would say that any focal length below 35mm would throw up problems
regarding edge distortion and aberrations.