Canon 2X Extender II vs. Tamron 2X SP AF Pro Extender: Comparison Shots

Discussion in 'Canon EOS' started by marknagel, Jul 7, 2007.

  1. I posted this question a couple weeks back and since bought a Canon 2X with the
    thought of selling my Tamron. I did some comparisons and found the Tamron to be
    a little sharper at the center and noticeably sharper at the edges. Obviously I
    kept the Tamron. Also you can stack the Tamron with the Canon 1.4x and it
    retains AF.

    The shots are taken at about 25-30 yards, Canon 5D, 300/2.8is, Wimberly
    head/tripod, shutter release, 100% crops, Jpg w/ default settings, AF, all other
    setting equal. I took about a dozen shots of each and picked the best, although
    they were all about the same. I did the comparison again and got the same
    results. Here are my results (photo is large):

    Comparison #1

    Comparison #2

  2. I am quite shocked by the results! I never would have believed it.

    When you say f5.6 does that mean that the f2.8 lens was wide open, and the camera adjusts the aperture reading taking the 2x into account?

    For the fun of it, it would be nice to test the 1.4x versus each of the 2x in an equal manner. By that I mean take the test shots with each adjusting your shooting distance to make the target the same size in each case. The shot with the 1.4x should be considerably sharper than with either of the 2x converters.
  3. John,

    Yes, all shots are wide open and one stop down. The camera reads the correct setting except when you stack them.

    I was going to do that with the 1.4X and Tamron when I get time. I returned the Canon 2X, so that won't be included.

    I did a couple shots with the Tamron 2X and Canon 1.4X stacked, and they are pretty good, and the AF worked.

  4. I would say this test represents the best 2X can do, because the subject lens is 300/f2.8 prime which is Canon's sharpest lens. On other less that best lenses the result will be less good.
  5. It is surprising.

    I have seen tests showing the Canon to be slightly sharper however, so it may be there is some process variation for even teleconverters.

    A small procedural note.

    When doing lens test there can be some AF variation from shot to shot. So it is unwise to compare single shots, you need to take the best of 3 at least.
  6. David,
    yes this is closer to the best of what it can do, but I was testing the Extenders, not the lenses, so thats what I was trying to achieve.

    as I posted above, I took the best of 12 shots to take into account AF variations, but all twelve shots were virtually identical.

  7. "Lester, as I posted above, I took the best of 12 shots to take into account AF variations"
    Yes you did Mark, sorry for missing that.
    It is a bit stunning, particularly as the TCs should be well matched to the 300/2.8, although I have heard the Canon TCs were designed to match the 70-200s, not sure if that is so.
    What is more stunning is how good the double stacking is, the 300 2.8 must be the sharpest lens Canon have.
    Have you considered returning the 2X and trying another?
    It would be very damming if two different serial number of 2X gave a poor result.
    Comparative tests I have seen in the past showed the Canon to be slightly sharper but so little that the difference was not really significant in normal usage. So seeing such a big difference does make me think there is something duff about that 2X.
    It is probably not much help but here are some centre crops from my 300 f4 IS on its own and then with the Canon 2X. Both wide open.
    <IMG SRC="" ALT="300 f4 IS @ f4">
    <IMG SRC="" ALT="300 f4 IS + EF 2X II @ f8">
    And a gain a stop down.
    <IMG SRC="" ALT="300 f4 IS @ f5.6">
    <IMG SRC="" ALT="300 f4 IS + EF 2X II @ f11">
  8. BTW they above plots have sharpening matched for the anti-alias filter.

    For info, the software analyse returned a average of vertical and horizontal MTF 50% points of 65 lp/mm and 47 lp/mm respectively for the lens and lens plus 2X both a stop down.

    Clearly the 2X is softer but still quite respectable. The visible difference in the one stop down shots is not that dramatic IMHO.
  9. Lester, I'm sure there is sample variation, but since I'm happy with the Tamron, and the fact it can stack with my 1.4X with pretty good results, I don't think I'll pester BH for another. If I run into a friend with one, thats another story and I'll post again.

    I am too shocked at the results. I have not seen an comparisons before, just read people's views and they are contradict what I found. Both 2X extenders and the 1.4x don't do so hot on my 70-200/2.8is. I'd say the results of even the 1.4X on my 70-200 are less sharp than the 300+1.4x+2X. I don't think they did a good job matching them to my 70-200 :)

  10. Hi Mark,

    Like you and others, I'm surprised by your results. I have not compared side by side with the Tamron (might do so now, though!), but have used the 2X II extensively on 300/2.8 IS and 500/4 IS, with very good results.

    Like you, I found the 2X II unacceptable on the 70-200/2.8 IS and don't use that combo. But, I do use the 1.4X II occasionally on that lens with very satisfactory results. I can't imagine that either TC was actually designed with the 70-200 in mind, though. I would think Canon matched both of them to the super teles, more than any other lenses.

    Unscientific, but my criteria are just that the combos give me shots that are sharp enough to print 8x10, 11x14 and larger, sometimes with some cropping to boot. Up until I got into the Canon EOS/EF system and tried the 1.4X, first, then the 2X, I had tried many other TCs in older camera systems and ended simply up not using teleconverters very much at all. One that I found to be acceptable was a 1.5X made by Kiron to fit several different systems. I am pretty demanding, but then and now it's all been pretty highly unscientific and subjective.

    And I should note, my 2X II tends to give a slight warm cast to images when used on the 500/4 IS specifically. That's easily fixed. In fact in many cases I might have been adding some warmth with a filter or WB adjustment anyway. So it really doesn't concern me and wouldn't keep me from using or recommending the 2X II.

    It would be great if you could try out some other Extender 2X IIs. I'd suspect the particular copy you had was out of whack for some reason. Your tests do speak well for the Tamron, though. I'll have to give one a try some time, and maybe in a little more scientific manner than I usually do! ;-)
  11. "Lester, I'm sure there is sample variation, but since I'm happy with the Tamron,"

    That is reasonable, I would expect any difference to be marginal anyway.
  12. ...But for the price difference, I'd hope it would be more:)

  13. Add me to the list of the surprised.

    Your test still leaves some questions without answers. Did you get a bad example of the
    Canon, did you get a great example of the Tamron? The test can't tell us the variance that
    exists within examples of these teleconverters.

    You did what I would have done though, you kept the better and less expensive tool.
  14. "Did you get a bad example of the Canon, did you get a great example of the Tamron?"

    I think Mark must have had a bad copy of the Canon going by my tests results with the little f4 brother of his 300/2.8. It is difficult to see the scope for a bad copy of a teleconverter, after all the element powers are low enough that they should not be overly sensitive to decentering assembly error.

    Presumably Mark was expecting a big improvement with the Canon, I would expect only a small improvement at best.

    Looks to me like there is only a $60 difference in price in the US, don't know about the UK as I have never seen the Tamron advertised.

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