Telephoto Zoom lenses and Teleconverters

Images taken with my Sigma 75-300 f4-5.6 APO at 300mm with and without Vivitar 1.4 TC (EOS mount) have been indistinguishable, except for slight colour shift. Moreover, the TC has even corrected a little bit the lens sharpness at the image edge! At times the lens was claimed to be the best consumer-grade zoom, esp. for its 300mm end.

I have shot the Canon EF70-200f2.8 with the Canon EF2x teleconverter and the Canon EF400f5.6 in side by side comparisons on Velvia and was unable to see any difference with a Schneider Loupe. I am not saying there is no difference but if there is it is minimal.

Well, I've shot prime Canon "L" glass with the Canon APO TCs and I even see a difference there, a significant difference with the 2x and a detectable difference with the 1.4x.

I've never seen results I'd call good from a zoom with a TC. People's standards vary. Maybe mine are too high!

I have used the Tokina (MF) 100-300 f4 ATX lens for six years and find it to be the best of this range.It is SHARP w/ great CONTRAST. Images are indistinguishable from Nikkor 400mm f3.5 at the 300mm end. Works very well w/ Nikon TC-16A.

Best $$ value on market in my opinion.

Here's a well presented comment from John Song which he posted on the nature Q&A forum. It addresses the issue of image quality even using one of the best APO zooms around.

"I've tested 70-200 F/2.8 w/ 1.4X and 2X and I find the result not satisfying for my purpose(birds). 70-200 w 1.4X gives pretty satisfiable image but it still is not close to Canon and Nikon 300 F/4(and too short for birds). I've tried on both Tamron 1.4X and Canon 1.4X, the center is about the same but the corners on Canon 1.4X is much sharper. I find 70-200 f/2.8 and Canon 1.4X quite acceptable for most of my work(newspaper). 2X was quite soft though. It is still acceptable for newspaper use, but I won't use it to work on my portfolio prints or slides(or magazine). If you don't want to print anything bigger than 8X10, it might be accpetable"

Canon are introducing a new L zoom this coming Photokina. It's the 100-400 4.5-5.6 IS L USM. It takes the TCs. According to the available web photos, it is a push and pull type zoom, and it is white.

It is also probably expensive... However, if image quality is not too bad, it might be a good option for the non-pro nature photographer like me, which only ocasionally needs to go longer than 300mm (even for that I use my 135 f/2 with the 2x TC, or the 180 macro with the 2x TC too).

I wonder if there are some basic misconceptions about the purpose of teleconverters. I thought of buying one myself recently in order to get better close-ups of some parrots nesting in a box I fixed to a nearby tree. My reasoning was that by using a 2X teleconverter with my 300mm Tamron zoom, I would effectively be getting a slightly inferior and much slower 600mm zoom which would nevertheless give me a better overall result provided I was able to keep the camera rock steady. It seemed logical that if I could enlarge the image on the negative 4 times (twice the width and twice the height) then it would need less enlarging at the printing stage resulting in a sharper picture. However, after reading the comments on this web page and pondering upon the subject, I've arrived at the conclusion that it makes little difference whether the enlargement is done prior to exposure (by using a teleconverter) or after exposure using an enlarger in a darkroom (or in my case, the computer), provided that your enlarger lens is of equivalent quality to the teleconverter, or in my case, provided the quality of my slide and negative scanner is of equivalent quality to the teleconverter. So, the question remains, "What is the use of a teleconverter?" Well, I can think of a few, and I stand to be corrected on these points. If you're lucky enough to own a really high quality lens that outperforms the film with regard to resolution (which wouldn't be too difficult in low contrast situations), then enlarging the image as it appears on the negative 4 times by using a high quality converter (you might call it "pre-exposure" enlargement) would enable the film to accommodate the full resolution capabilities of your high quality lens. Another use would be for people who don't do any enlargement, who are satisfied with postcard size prints. A teleconverter can be a sort of partial substitute for a darkroom enlarger. (Enlarge the image before it hits the negative, sort of!) In my situation, where a Nikon LS2000 scanner is a substitute for an enlarger, I wonder if scanning an image 4 times the size but containing essentially the same information as the image without the teleconverter, might produce a better result bearing in mind that consumer grade scanners are unlikely to extract all information from the image. The larger image would contain 4 times the number of pixels after scanning. Maybe someone more knowledgeable than me might like to comment on this.

Bob, in the opening you mentioned the issue of a "well matched" lens and teleconverter combination. I have been contemplating buying one of the new Nikon 80-200 AFS lenses and the 2x teleconverter. Why not just get a 400? Price is the obvious answer, but it also has to do with the sports photography that I do, where having no ability to back away when the subjects are running towards me forces me into the 150-400/500 type of camp. I have tested the combination just in the shop, and the focus speed seems exceptional. The question is: is this indeed a well-matched combination where I would get results much better than I would with the third party lenses mentioned above? Or would I be better off just renting the 400 lens when I need it, and not have the flexibility? In other words, what kind of quality loss could I expect with the Nikon TC-20E and the 80-200 AFS combinations compared to the 400 AF?

Marc Alberts

In summer 1999 the French magazine Chasseur d'Images compared telezoom+TC against making a comparable partial enlargement of a photo taken with the zoom alone. Although they weren't happy about neither of these two options on an absolute scale, they concluded that the former option was better, if those are the only choices available to you.

Have lens developments moved on since your comments ? Refer to the Tamron & Sigma 28-300mm f3.5-6.3 zoom lenses !

I have been using a 80-400 Nikon VR for about 6 months now. I am always suprprised at how sharp it is. I decided to try a TC201 since I have a hole between 400mm and 1000mm. I was concerned about vignetting more than sharpness. I have developed the first roll and was pleasently surprised that I can't detect any vignetting even at 800mm. I even shot just the sky. I shot two portraits of my wife at 400mm. One at normal 400 the other at 200 with the TC. On a 5x7 at first glance I didn't see a difference unitl I examined her necklace with a magnifieng glass. That was the only part of the picture I could detect that sharpness had been compromised. The image is still fairly good. At 800 the images are reasonably sharp. The lens is hard to manually focus since moving the ring very slightly changes quite a bit. Of course you lose the VR also. At 800mm the poor tripod mount and lack of mirror lockup on the F100 does not help me either. It is still not too bad of a combo if you have the time to set the lens up for a shot. One thing I really like is the size. I can now carry 20mm and 28 through 800mm in my bag with ease. I did not expect the TC201 to do this well with at the 400 setting. The TC301 will not physically fit the 80-400VR.

Al

Taken with the Canon EF 100-400 L IS USM on a EOS Elan 7E

I can confirm that the Canon 100-400 L IS USM is a great lens. Image quality is very sharp through the intire focal range, only slightly dropping off at 400mm @ 5.6. The Image Stabaliser function really works well, i have been able to take photos handheld at 1/60th at the 400mm end and still get very sharp results.

Another point not addressed above; I can't speak to all makes and models, but the body I'm saving for, (a Canon Eos Elan 7,) will not autofocus with an aperture smaller than 5.6, thereby rendering many lenses manual focus only with the addition of a teleconverter.

Craig,

I'm not sure of your previous previous comment "a Canon Eos Elan 7 will not autofocus with an aperture smaller than 5.6". I bought the eye-control version of this camera (it's called EOS 30 over here) about two weeks ago and have noticed no such shortcoming.

I'm lucky enough to have a 300mm f/4? "white" canon lens on loan and have put 4 rolls of film through with it almost always set at f/4. The autofocus has been amazing... i've taken great shots (in my humble opinion) of fast flying birds with the shutter speed around 1/1000 to 1/2000th marks and the autofocus has been excellent. The only hassles I've had were on a couple of fast panning shots i've focused on the background rather than the bird, and i'm pretty sure that was because i was struggling to keep up with the birds with such a large lens (compared to previous experience) at a realatively close distance (30' or less).

But back to the TC debate...

I don't have one yet, but from what I've been told, stick to a canon TC for the Elan 7 or better body especially if you're going to have good canon lenses - the no-name TC's can't keep up with the autofocus systems.

Cheers from Down Under

Cameron, If I understand what you're saying, you're shooting at f4 with no problem with autofocus; That's not inconsistent with my comment, as an aperture of f4 is actually a *larger* aperture than f5.6 (The f stop number being the focal length / aperture, so a smaller f stop number is a larger aperture [If the aperture equalled the focal length, the f stop would be "1"])

Whoops... I knew that! It appears I had a brain freeze...

At the end of the day it is, as has been said already, about cost,if I had unlimited funds, I would get a 400mm or longer but for most of my work, which is mainly for pleasure I would not use it enough to justify the cost. But I already own a 75-300mm USM (not the best not the worst) so if I get a x1.4 TC I would have a 75-420mm f4-f8, or a x2 (75-600 f4-f11) for approx £200. I'll never win prizes for sharpness, but L lenses or even IS lenses are out of my league. I could afford a cheapo mirror lens but then what would be the difference. The EOS 3 central focus point wil AF down to f8 so even with some TC's AF will be possible.

Craig,

I have a Elan II (the previous version of the Elan 7) and it autofocuses absolutely ok at all apertures. I have used it with three different Canon lenses 100-400mm F/4.5-5.6 L, Canon 28-135mm, 50mm f/1.8 and it works fine. Some times under really low light autofocus does not work correctly but otherwise it works great.