Which teleconverter?

[obi-wan-yj]

When buying my latest telephoto zoom for my XTi/400D, I had to compromise, and

ended up getting the Canon 70-300 f/4-5.6 IS. It's a fine lens at that focal

length, but I really need something longer for wildlife, and buying another $1K

super-tele lens is out of the question.

 

I think a 1.4x tele-extender would work best for me right now. Since most of my

wildlife shots are near dusk, I don't want a 2x teleconverter, as manual

focusing in dim light at f/11 on my XTi's viewfinder is terribly difficult. In

reading a number of reviews, it seems there's a wide difference in image quality

among teleconverters. I upgraded lenses to gain IQ, and I don't really want to

lose it again with a teleconverter. What would be the best teleconverter to get

to maintain full electronic functionality for Canon non-L EF and EF/S lenses? I

suppose I could live with EF only (not EF/S), since my longer lenses are all EF,

and only my wide angles are EF/S.

 

Although I currently use a crop sensor, I hope to upgrade to a 5D someday, so I

don't want to buy something that vinettes badly on a FF sensor.

 

Any first hand experience with good or bad 1.4x teleconverters?

[bobatkins]

I use the Tamron-F. There are some comments and sample images here (http://www.bobatkins.com/photography/reviews/ef_70_300is_review.html) and here (http://www.bobatkins.com/photography/reviews/canon_EF_70-300_II.html).

 

Realize that a 1.4x on the 70-300IS will very likely give you a lens that must be manually focused. On my 40D the combination tries to AF but fails and focus oscillates. Image quality is OK. It's better than upsizing the image without the TC, but it's not going to give you a supersharp 420mm lens. You may in fact want to stop down a stop (to 420mm f11) for best results.

 

A TC on a 70-300IS is a stop gap measure and not a subsitute for a longer lens. It's useful at times, but if you want a good longer lens it will cost you a lot more than the $100 or so you'll pay for a 3rd party TC.

 

No TC that I know of will work on EF-S lenses. Not the Canon TCs for sure and I don't know of a 3rd party TC. This shouldn't be a big deal. You don't want to put a TC on a wideangle lens and most of the EF-S lenses are wideangle. There is the EF-S 55-250, but I'm not sure it's good enough to take a TC anyway.

[obi-wan-yj]

I know about the probable lack of AF. That was a compromise I chose to live with in order to get a sharp, light-weight, inexpensive telephoto lens. I'm used to manually focusing my el-cheapo 500/8, and I can do it with some degree of accuracy, but the results from that lens are suitable only for screensavers, not prints.

 

For shooting wildlife, I would have preferred something like Sigma's 80-400 or Canon's 100-400. However, I'm also a "soccer dad." I rented the 100-400 for a day and shot my son's midget football game. After an hour of pacing up & down the sidelines with that beast, I decided that I'm not ready for a 4-lb lens at this stage in my life. I'm also planning a 4-day backpacking trip this summer, and the three pound difference between the 80-400 and my 70-300 is significant.

 

So, the 70-300 plus a 1.4x teleconverter seemed to be a better way to get to 400+mm, at least until I start making enough money off photography to subsidize my lens purchases.

 

There seem to be two classes of 3rd party teleconverters: "consumer grade" TC's for about $100, and "pro grade" TC's for $200. It seems the latter will support wider apertures, but my fastest telephoto lens is only f/4-5.6. Is there any other difference between these two? Am I likely to get better image quality from the pro grade?

[ken munn]

I use a Kenko TC, 7-element version. Mine is a x2. I'd expect the x1.4 to be better. I'm

pleased with it.

 

Attached shot is detail from the 70-300 IS x2.<div></div>

[obi-wan-yj]

When you say "detail," do you mean a 100% crop, or a scaled down version of the entire photo? If the former, from where in the image was this taken?

[ken munn]

Ooh, technical questions! Forget I said detail.

 

No, actually that's the full frame shot.

 

Attached is a shot of the scene taken at 30mm (50mm equivalent on my 40D)<div></div>

[bobatkins]

I can tell you that in the center of the image, the Tamron-F 1.4x pretty much equals my Canon 1.4x on an EF 500/4.5L. On APS-C the edges are similar, though on full frame the Tamron shows some vignetting (the optics are smaller than those in the Canon TC) and the corners aren't as sharp. I've never tried the "pro" version.

[bob_howdeshell]

I use the Kenko 1.4X Teleplus Pro 300 DG Teleconverter on my Canon 100-400 with good results. I have the pins taped and the auto focus works well.

[obi-wan-yj]

Have you compared that Kenko Pro against any other teleconverters to see how it stacks up?

 

When you tape the pins, does that mean the camera has no knowledge of what the lens's aperture is set to? I.e., no aperture info in the EXIF data, and no ability to stop the lens down beyond wide open?