70-400 G with Kenko and Tamron 1.4X TCs

Hi All

First of all, my copy of the 70-400 G is sharp at all FLs and apertures. I'm extremely pleased with the lens. However, after reading some preliminary reports of the 70-400 G with various TCs I decided to find out for myself. All my test pics were shot handheld, wide open, and using static objects at 400mm. Here goes:

70-400 G with the Kenko Pro 300 1.4X TC:

AF was very slow, lots of hunting, and sometimes focus lock wasn't achieved. The IQ with the Kenko TC was consistently worst than the IQ with the Tamron TC. Cropping the 70-400 G images consistently yielded noticeably better images then those produced with the Kenko 1.4X TC. Conclusion: The Kenko 1.4X TC is of no or very limited value when used with the 70-400 G. I plan to sell my copy of the Kenko TC.

70-400 G with the Tamron Mx-AF MC4 1.4X TC:

AF was reasonably fast, little hunting, and focus lock was always achieved. I don't believe AF is fast enough for most BIF pics. IQ with the Tamron TC was noticeably better than with the Kenko TC. Some pics with the Tamron TC weren't very good; however, some of the pics with the Tamron TC were just as sharp as those taken with the 70-400 G only. In many cases, pics with the Tamron TC were just as good or better than those made with the 70-400 G after cropping. It must be pointed out, my success rate was much higher when using only the 70-400 G than those taken when using the Tamron TC. Conclusion: I probably won't use the Tamron TC with the 70-400 G very much, because I'm just not steady enough to produce enough good handheld pics to justify the effort. However, for those who use tripods and those who are very steady when handholding - the Tamron Mx-AF MC4 1.4X TC holds great promise. I suggest anyone who wants to experiment should find an used copy of the Tamron MX-AF MC4 1.4X TC, and I guarrantee they will have some fun.

Your comments will be appreciated.

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Thanks, Ed
Torrance, CA

Thank you Ed.

I have seen photo's with some excellent lenses where Tc's, even stacked Tc's, were used and the results looked terrible. But for some reason the users were selling the idea as they were selling it to themselves too, as great.

Your review is the first that seems to have the integrity that will provide some very useful information.

The quality of the 70-400 in my experience should not be compromised for some additional reach, just to get inferior photo's. Why spend good money on good glass just to degrade the quality for more reach? I see no logic in that for me at all.

But thanks to you I can now see that for tripod use at long distances, in good light, the Tamron 1.4 sounds very good.
You have helped me.
Thank you.
Darwin

Darwun D Solus said:

Thank you Ed.
I have seen photo's with some excellent lenses where Tc's, even
stacked Tc's, were used and the results looked terrible. But for some
reason the users were selling the idea as they were selling it to
themselves too, as great.
Your review is the first that seems to have the integrity that will
provide some very useful information.
The quality of the 70-400 in my experience should not be compromised
for some additional reach, just to get inferior photo's. Why spend
good money on good glass just to degrade the quality for more reach?
I see no logic in that for me at all.
But thanks to you I can now see that for tripod use at long
distances, in good light, the Tamron 1.4 sounds very good.
You have helped me.
Thank you.
Darwin

Click to expand...

Hi Darwin

I appreciate your comments. A fellow DPR poster found the Tamron MX-AF MC4 1.4X TC on ebay for me. It wasn't listed correctly, but the photo clearly showed it was the model I was looking for. I paid $80, and I've already had that much fun.

I sincerely hope your experience will be as good as mine. I'm convinced the Tamron TC will be benefical when mounted on a tripod.

Take care.

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Thanks, Ed
Torrance, CA

I guess I don't understand why you would just not crop the image from the 70-400 instead of trying to use a 1.4 converter?

If the image quality ends up about the same when cropped and it focuses better -why bother with the converter?

Or do you think you can get better IQ with the converter?
--
tom power

I meant to add that I always thought that converters were really meant to be used with larger (2.8 or bigger) aperture lenses?
--
tom power

tompower53 said:

I meant to add that I always thought that converters were really
meant to be used with larger (2.8 or bigger) aperture lenses?
--
tom power

Click to expand...

Hi Tom

For me, I doubt there is really any great advantage to using the Tamron TC handheld. My success rate with the TC handheld makes cropping a more appealling choice for me.

However, I believe a very steady photographer or someone who uses a tripod can use the 70-400 G plus Tamnron Mx-AF MC4 1.4 TC to their advantage. Their success rate may not be real high, but they will produce enough pics that are better than cropping to justify their efforts.

Just my opinion - I wish I had the nerves to handhold this combo.

--
Thanks, Ed
Torrance, CA

Well have fun with that 70-400 it sounds like a darn good lens.

I have the Sony 70-300G, Tamron 70-200 and 200-500 so I am probably not going to get one of those anytime soon.

Now if they made a 70-400 f4 G maybe I could get rid of all the above then buy a little wagon to help me carry it around.
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tom power

tompower53 said:

Well have fun with that 70-400 it sounds like a darn good lens.

I have the Sony 70-300G, Tamron 70-200 and 200-500 so I am probably
not going to get one of those anytime soon.

Now if they made a 70-400 f4 G maybe I could get rid of all the above
then buy a little wagon to help me carry it around.
--
tom power

Click to expand...

Hi Tom

Based on the size of the 70-400 G (it's bigger than the Tamron 200-500), you'd need a wheelbarrow to haul a 70-400 f4 around in.

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Thanks, Ed
Torrance, CA

Nice review, but you definitely need to show some samples for IQ!

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http://www.flickr.com/dr4gon

dr4gon said:

Nice review, but you definitely need to show some samples for IQ!

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http://www.flickr.com/dr4gon

Click to expand...

I don't have a web site for my photos. I really need to get - it's time I start posting some of my photos. I'm sure I'd benefit from helpful comments.

Do you know of any easy to use web sites? The simplier the better. I'm not very good with computers and new stuff.

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Thanks, Ed
Torrance, CA

Try photobucket.com its free. The Sony/Minolta APO 1.4TC is a much better match for the G lens. It cost 3x more than the other TC, as much as another lens. It is matched to the lens by the manufacturer. You will have to MF. Pretend like you are 50 years old.

According to another thread on this forum, Kenko makes both TC.

http://forums.dpreview.com/forums/read.asp?forum=1037&message=31464544

I just read the thread, Kenko makes TC, but,not APO matched.

And even if you compare the lower quality TCs from either company, they all have different specs in terms of element/groups construction.

aksockeye said:

Try photobucket.com its free. The Sony/Minolta APO 1.4TC is a much
better match for the G lens. It cost 3x more than the other TC, as
much as another lens. It is matched to the lens by the manufacturer.
You will have to MF. Pretend like you are 50 years old.

Click to expand...

I don't doubt for a minute that the Sony 1.4X TC is better; however, I was testing TCs that maintain AF.

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Thanks, Ed
Torrance, CA

It's hard to believe that the Kenko and Tamron are from the same family of TCs. Even if you ignore sharpness etc, the Kenko focused so much slower and failed to find focus on occassions.

I think the Tamron might be an older model; however, I don't know. There is no doubt in my mind that the Tamron is clearly superior in everyway when compared to the Kenko on the 70-400 G. In my opinion, operator error couldn't even come close to accounting the differences I noticed.

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Thanks, Ed
Torrance, CA