Canon TS-E 17mm f4L with Canon 1.4x extender vs. Canon TS-E 24mm f3.5L

June 13, 2010

Canon 17mm TS with 1.4x converter

Today I compared my two Tilt/Shift lenses. My old Canon TS-E 24mm f3.5L (which doesn’t spend much time on my camera anymore) and my Canon TS-E 17mm f4L with the Canon 1.4x extender (resulting in also 24mm effective). The maximum aperture of the TS-E 17mm f4L becomes f5.6 with the extender but because I mainly use it on a tripod stopped down to f11 it’s not a problem for me. The comparison I made was with both lenses stopped down to f11. The images were shot with a Canon EOS 1Ds MkIII mounted on a tripod. Will the quality of the TS-E 17mm f4L with 1.4 extender be close enough to the TS-E 24mm f3.5L so I can save room in my camerabag? And create some space in my wallet at the same time (or should I say fill up some space in my wallet)?

The results

Top: Canon TS-E 24mm f3.5L. Bottom: Canon TS-E 17mm f4L with Canon 1.4x extender. The extender-combo gives a little more wideangle (which is logical: 1.4 x 17 = 23,8).


 In detail
100% crops, those were taken from the areas marked with a red square:

The four Out-Of-Camera 100×100 pixels crops show the Canon TS-E 17mm f4L (with Canon 1,4 extender) on the left and the Canon TS-E 24mm f3.5L on the right.

The difference is unexpected: the fringing that can be seen here belongs to the bare 24mm and the 17mm is surprisingly clean. I actually would have expected it to be the other way around. The optical quality of the TS-E 17mm f4L amazed me quite a few times when I worked with it ‘bare’ but it keeps amazing me!

The larger, 400×400 pixels crops (17mm with extender at the top, 24mm at the bottom (all crops are unsharpened, unedited files)) show that the sharpness of the two lenses is about equal.    

Although the fringing gives the 24mm a bit of a mushy, almost motion-blurred character, on A4-size prints I’ve made from the 17mm and 24mm-files there’s no way of telling them apart. On A2-size prints the difference starts to show but only when looking very closely.

The second pair of crops below looks very similar. Only the fringing in the bottom corner (left) gives away what was taken with the TS-E 24mm f3.5L…

An update: recently I tested the 1.4 extender version III against the 1.4 extender version II. On the TS-E 17mm, that’s where it would be of most interest for me. I hoped it would have less distortion and that turned out to be true. The II needs a geometric pinch-correction of 3,5% to get rid of the barrel distortion and the III ‘only’ 2%.
But, at least with my camera/lens-combo, the II has slightly sharper edges than the III. Even after correcting the distortion! So it’s a step forward on the distortion and a step back on corner sharpness. As the images shot with each of the two extenders will have to be corrected for the distortion anyway, I’ll keep the € 500 euro in my pocket and do not upgrade my 1.4 extender to the III-version.
And in case you’re wondering where the test results can be seen: I didn’t include samples because I shot a not too inspiring brick wall for the test, and I think there’s too many of those brick wall images already on the internet…


Polariser or other filters on Canon 17mm Tilt/Shift

May 31, 2010

Canon 17mm TS with Cokin X-pro filterholderBecause of the need for a polariser to be used on my 17mm tilt/shift lens and the lack of an industry-made solution, I decided to create my own custom-made filterholder.

– The largest filterholder there is on the market, the Cokin X-pro.
– A spare lenscap so I could use its bayonet for easy attachment to the lens.
– thick black paper (backgroundpaper) to cover the open space between the holder and trfnal (The Ring Formely Known As Lenscap).

The Cokin X-pro filterholder has a large enough diameter to avoid vignetting (working on full-frame), even when shifting the 17mm to the maximum setting. But, strangely enough, the polariser has a smaller diameter than the holder itself. I’d say that’s a serious design flaw: it means the rim of the filter causes vignetting at maximum shifting… No vignetting problems when using Cokin rectangular filters but I could not find a manufacturer that makes them large enough (130x170mm). Cokin only produces round polarisers…