What is your opinion on using a 1.4x extender (Canon, Kenko, Tamron) on Canon EF 135/2.0, especially wide open?
Usually, an extender work well on long lenses and not so well on short lenses. The 135mm is sort off in between. Also, using it wide open can present a problem for the extender because of a large angle of the incident rays.
Anybody, who used this combination, please, chime in.
When I got my 135L I already had a Kenko Pro 1.4x and hoped to use it with this lens. Quick tests with my Canon 5D showed that the IQ was not qood until stopped to f/5.6 (see http://alexsouvorov.smugmug.com/gallery/4361743_Xcg5i#256026437_9hLKF). I never had any problems with this extender and 300/4 IS. I purchased a Canon extender and it gives much better results. The image degradation, if present, is very minimal even vide open. One of the explanations I have is that the opening for the Canon extender is much wider. I don't have tests with the Canon extender online right now but I still should have them on my home computer.
Alex wrote:
When I got my 135L I already had a Kenko Pro 1.4x and hoped to use it with this lens. Quick tests with my Canon 5D showed that the IQ was not qood until stopped to f/5.6 (see http://alexsouvorov.smugmug.com/gallery/4361743_Xcg5i#256026437_9hLKF). I never had any problems with this extended and 300/4 IS. I purchased a Canon extender and it gives much better results. The image degradation, if present, is very minimal even vide open. One of the explanations I have is that the opening for the Canon extender is much wider. I don't have tests with the Canon extender online right now but I still should have them on my home computer.
It works really well. I recently compared USAF 1951 test chart resolution results for the 135/2L with Canon 1.4x Extender and Tamron SP 1.4x teleconverter, and with SMC Pentax 200/2.5, Canon 70-200/2.8L IS, Canon 100-300/5.6L, and Tokina AT-X 24-200/3.5-5.6, with all of the zooms at 200mm. The tests were done with a 20D at ISO 100 on a tripod with MLU. I often use the 135/2L with 1.4x on my 5D, but I haven't tested it. Here's the calculated resolution in lines per mm (lpmm), in order from best to worst for a few different conditions. Anything above 50 lpmm is pretty darned good. The 5D sensor resolution is about 60 lpmm, 20D is 78 lpmm - same as the 1DsIII.
centre resolution, wide open (135/2 at f/2, 100-300/5.6L at f/5.6, etc.)
68 lpmm EF 100-300/5.6 L
64 lpmm EF 135/2 L USM + EF 1.4x
57 lpmm EF 135/2 L USM + SP 1.4x
55 lpmm EF 70-200/2.8 L IS USM
48 lpmm AT-X 24-200/3.5-5.6
48 lpmm SMC Pentax 200/2.5
centre resolution at f/8
78 lpmm EF 70-200/2.8 L IS USM
68 lpmm EF 100-300/5.6 L
64 lpmm EF 135/2 L USM + EF 1.4x
64 lpmm EF 135/2 L USM + SP 1.4x
61 lpmm SMC Pentax 200/2.5
54 lpmm AT-X 24-200/3.5-5.6
corner resolution, wide open (135/2 at f/2, 100-300/5.6L at f/5.6, etc.)
61 lpmm EF 100-300/5.6 L
57 lpmm EF 135/2 L USM + EF 1.4x
48 lpmm SMC Pentax 200/2.5
44 lpmm EF 70-200/2.8 L IS USM
40 lpmm EF 135/2 L USM + SP 1.4x
34 lpmm AT-X 24-200/3.5-5.6
corner resolution, at f/8
68 lpmm EF 100-300/5.6 L
64 lpmm EF 135/2 L USM + EF 1.4x
64 lpmm EF 135/2 L USM + SP 1.4x
61 lpmm SMC Pentax 200/2.5
55 lpmm EF 70-200/2.8 L IS USM
43 lpmm AT-X 24-200/3.5-5.6
Jim,
Interesting, from your data the Canon extender is much better, especially at the corners. Actually, it shows that Canon does not even make the corners that much worse! It also chimes well with Alex's assessment of Canon vs. Kenko.
Sharpness wise, you will find little difference between the 135 f/2L and the 135 f/2L with the Canon 1.4x II. The only problem that I seem to have noticed is with bokeh: with the 1.4x II, it tends to produce some double lines. Nothing horrible by any means, but it's noticable.
I tried my 135L with a Kenko 1.4x on my 1Ds2 the other day and certainly found out that the combination was not at all successful wide open, it looked like the photos were taken with a really nasty consumer zoom. Unfortunately I did not stop down for any of the handful of shots I made with the combo but I expect it to improve a lot stopped down. The 80-200L was far happier with the Kenko wide open, strangely.
After reading this thread I got inspired and took the 135+EF1,4-II (on a 1D2) for a spin... and was pleasant surprised. Even if the lightning was pretty dull, I found that the qualities of the 135 was there even if only stopped down 1/2 stop.
Indeed I think I will use this combo more often rather than drag my 70-200/2,8 along too.
, send me email or PM.