Extension Tubes with the 400mm f/5.6 L

I have read that quite a few people use an extension tube with the 400mm f/5.6 L when photographing small birds in order to reduce the minimum focus distance and get closer, to fill the frame more effectively.

I'm not sure if this a common use, but I would like to use an extension tube simply to bring my subject closer, so not really the same as achieving a smaller minimum focus distance.

My favourite bird photography spot is exactly 30 feet from my hiding place, which for small birds is still too far away. A goldfinch-sized bird cropped nicely only uses about 10% of the original frame, using the 400mm on my 20D.

Do any of you use extension tubes with your 400mm f/5.6 L (or any other telephoto) for bringing your subjects closer?

I am interested in finding out how each particular extension tube affects the maximum focus distance too, as well as depth of field, so that I know how far past my subject distance I can focus my lens. I have no idea how to work out maximum focus distance when using extension tubes, but would depth of field simply be calculated using the focal length of the lens with the length of the extension tube added (e.g. 400mm + 20mm = 420mm)?

The only information I can find regarding the use of extension tubes relates to minimum focus distance, when I'm mainly interested in maximum focus
distance.

Thanks

Mike

If your subject is within the normal range of focus for that lens (i.e. beyond the MFD such as 30 feet for the 400/5.6) then do not use an y ext. tubes. You will not gain anything and you will lose some light. If you want longer lenses then TCs are your answer. The 1.4x TC on the 400/5.6 becomes a 560/8 lens that still can focus at 30 feet. Bigger image.

Okay, thanks. I have a 1.4x TC on my wish list, but they're quite expensive!

Surely I would gain magnification with an extension tube, and also lose light with a TC wouldn't I?

Mike

Do not think of it as gaining magnification, just get to focus closer with tubes. 1.4x TC loses 1 f/stop. Get a used TC to save money. Tamron SP 1.4x TC is my favorite. I have 2 of them. The fit all lenses and can be stacked.

Attached is a table of min/max focus distances with various tubes and the 400mm f5.6. Nothing scientific about the test, I just attached the tubes and measured the distances with a tape rule but it gives you an idea.

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That's very helpful Roy, thanks.

Mike

What camera do you use?
I ask because my 40D had focus issues with knock off teleconverters. Autofocus worked great, but I dealt with the majority of the photos OOF. My Point and shoot was sharper. These were clearly miss-focuses from the autofocus. I noticed the 40D would 'jump focus' sometimes you could see it in the viewfinder. This was with the Tamron 1.4x and the Promaster 2x. [they worked great on my 20D, so it must be the camera focus system.] I finally gave in and bought the canon 1.4x and it works well. However I got tired of the 40D focus quirks and bought the MKIII which autofocus works effectively with all teleconverters, even stacked. And for more ISO ability. So it may depend on which camera you have. I'd try them in store before buying a tele.

The 12mm tube is excellent between 4 ft. and 15 ft. No extra glass. Autofocus works great. Sorry I do not use the 400 5.6 but my friend does w/1.4x canon tele and has excellent results, although she has also the MKIII which she claims is the only way to go with a 5.6 lens+tele autofocus. The 400 5.6 +tele was not dependable for autofocus on her 30D. She uses higher ISO to solve the darker/slower image[In fact uses auto ISO when her teleconverter is on.]

Most teleconverters work excellent in manual focus. The focus issues are more tuned with camera than the tele. Even cheaper lenses do well with them in manual. Auto-focus is the issue for clarity.

Thanks for your reply

I'm using a 20D. I would like a 1.4x TC, but I would only consider the Canon one. The extension tubes I would like anyway for macro, so I'll still get myself a set when I can.

Mike

Mike-DT6 wrote in post #6569621
Thanks for your reply

I'm using a 20D. I would like a 1.4x TC, but I would only consider the Canon one. The extension tubes I would like anyway for macro, so I'll still get myself a set when I can.

Mike

I have both Canon 1.4 tc and Kenko Pro 1.4 and IMO there is nothing to choose between them in terms of IQ. You need to remember that the Canon tc will only fit certain Canon lenses whereas the Kenko will fit almost any lens. I use a tc with my Canon 100mm f2.8 macro sometimes and the canon will not fit so I use the Kenko.

I originally thought that sticking to the Canon 1.4x TC would be the only sensible choice, as I thought it was designed for L series lenses, so would be better than the alternatives for image quality. Am I wrong in thinking this?

I did some reading after what you said and have found that some people claim the Kenko to be as good as the Canon with regard to image quality. Also I have seen the Tamron SP model mentioned and some claims were that it is better than the Canon model. Surely that can't be true can it?

Considering that the alternatives cost half as much and have equal performance, what reasons are there for buying the Canon model?

Mike

Mike-DT6 wrote in post #6558218
Okay, thanks. I have a 1.4x TC on my wish list, but they're quite expensive!

Don't forget that you won't be able to autofocus with a 1.4x on your 400 f5.6. Not unless you do the pin-taping trick. Even then AF will be paifully slow in all but great light.

Thanks, yes I realize that. I use manual focus a lot with this lens anyway, so it wouldn't be too much of a problem.

Mike

Mike-DT6 wrote in post #6576096
I originally thought that sticking to the Canon 1.4x TC would be the only sensible choice, as I thought it was designed for L series lenses, so would be better than the alternatives for image quality. Am I wrong in thinking this?

I did some reading after what you said and have found that some people claim the Kenko to be as good as the Canon with regard to image quality. Also I have seen the Tamron SP model mentioned and some claims were that it is better than the Canon model. Surely that can't be true can it?

Considering that the alternatives cost half as much and have equal performance, what reasons are there for buying the Canon model?

Mike

Mike, I have done several test with both converters and the 400mm f5.6 and IMO there is little to chose between them as far as IQ goes (with this lens anyway). I bought my Kenko Pro direct from Hong Kong at less than a third of the price of the Canon.
I have heard of someone who says that the Canon is better than the Kenko Pro when used with 500mm f4 but I guess if you ever come to buy a 500 f4 you could afford a Canon tc as well Also the Canon has better weather sealing I believe.

As already stated I can use the Kenko with my 100mm macro lens whereas the Canon will not fit.

BTW I understand that the Kenko Pro and the Tamron SP are the same converter with different badges although I cannot confirm this myself.

Thanks Roy

I'll definitely be considering the Kenko or the Tamron now, although I must admit that my camera bag would look better with all-Canon inside it - if only for OCD reasons!

Yes, I read about the similarities with the Tamron. I was doing some reading and apparently Tokina, Hoya and Kenko are the same company (THK Group). I also read that Hoya supplies lens glass to Nikon, Canon, Sigma, Tamron, Tokina, Olympus, Sony and more.

Mike

You might get more focus attempts with the Tamron or the Kenko. I switched to the canon II 1.4x for the 40D amd MKIII because of autofocus issues with the 40D + teleconverters. I think you'll be ok with the 30D, and possibly the knockoffs will do better because they don't report aperture, so autofocus should work.