can anyone tell me if CANON 7d can give autofocus with 500mm canon EF L lense and Sigma 2x tc ?
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can anyone tell me if CANON 7d can give autofocus with 500mm canon EF L lense and Sigma 2x tc ?
If this is a reporting TC then I don't think so. The 7D can AF only at f/5.6, 1D bodies up to f/8.
Hi Mital Axel is totally correct ... even if using a 1.4X would suggest to stick with Canon converter !! Among Canon converters there is a significant difference from the current to previous model !!
Hola Al!Quote:
Originally Posted by Alfred Forns
Are you saying that the 1.4TC is somewhat different to the 1.4II TC? if so, what's the difference? Thanks for your replay.
Juan the new appears sharper !!! When I switch back from to Canon I bought two used like new converters and did not seem right .. after a few days looked at them closely and both were the original design. Sold and replaced with current model. Don't know if it was just me but that is what I observed.
Thinking back should have done some testing on targets !!!
dear alfred, axel and juan
my friend do have canon 40d, 500mm, 100-400, 1.4 canon TC and 2x sigma tc.
now he is thinking for upgrade and his main goal is to get the body work autofocus with 2x tc of sigma on his 500mm EF L lens.
he heared that 5dMII gives that but today i read somewhere that on 7d sigma2x also allow autofocus with 500mm.
just want to hear what people here think or may used or not ?
If it is for static subjects your friend might focus manually. Cameras with non-reporting TCs attached try to acquire AF but it oscillates and can be quite slow. If I were in his position, I would stick with the 1.4x TC on the 500f/4.
yes for a better quality photographer it is true Axel. but here is little diff case as he is more of bird watcher and keen into taking records of birds from far he wish to autofocus from far to take records and thus he wish that if 7d can give autofocus with sigma 2x he would be ready with budget otherwise he has to make long wait for next budget for 5dm2.
thats why i am posting here to know if it is possible to get autofocus with SIGMA 2x tc on 500mm with 7d ?
Maybe someone who owns a 7D can chime in, but theoretically the 7D won't autofocus with a 2x TC and a f/4 lens.Quote:
Originally Posted by mitalpatel
Yes, it's possible with Live View, it's slow but accurate.Quote:
Originally Posted by mitalpatel
didnt understood that its possilbe with "live view" ?Quote:
Originally Posted by Jia Liu
AF in Live View doesn't use phase detection and AF sensor, so it's not limited by f/5.6. As long as there is light, it will focus using contrast.Quote:
Originally Posted by mitalpatel
Mital,
The only way to get the 7D to AF with a 2X TC and 500 is to use live view contrast detect AF but it will be painfully slow and would not lock in most situations. There is really no point using such high pixel density camera with a 2X converter and 500mm lens, especially third party converter like Sigma. The combo will not have the optical resolution needed for the 7D sensor and you will get soft images with bad contrast most of the time. It would be better to use the 500 with 1.4 which will deliver much better results and also will AF using camera's main AF sensors. With 18 mpixels you can get plenty of detail on the bird even if it small in the frame if the image is sharp.
Good luck
A little advice here, I have heard that the 7D does not like converters and I can confirm that.
Yesterday I took my new 7D with the updated Firmware and my 300 f/4 L IS, 400 f/5.6 L and my 1.4 II X converter out to test this.
My 5D MKII and 1D MKIII lose almost no IQ with the 1.4 on the 300 f/4 (420mm) but the 7D DOES.
I compared shots with the lens only, with the 1.4 and with the 400 clean and the results were 300 f/4 clean, perfect, 400 f/5.6 clean, perfect, the 300 f/4 + 1.4 a noticable loss of IQ which is what I had heard possibly because of the tightly packed 18 MPs on a small sensor so with a 2X I think it may well be much worse.
Make sure to check before you buy.
This also could be caused by a auto focus calibration issue when adding the TC.Quote:
Originally Posted by Christopher C.M. Cooke
Don, could you add some more info for me on this, I am new to this camera but I have used the 1.4 TC without any calibration issues on 1DsMKII, 2 30Ds, 1DMKIII, 450D, 350D, 5DMKII.Quote:
This also could be caused by a auto focus calibration issue when adding the TC. <!-- / message -->
The focus appears accurate but the IQ is substandard and the camera is going back to Canon today.
Thanks Don.
Thanks for the explanation Al. It's a good thing to consider for a future buy.Quote:
Originally Posted by Alfred Forns
Christopher, The way I understand it is that Canon considers a camera or lens to be within tolerance if they are +5 or -5 to their baseline of 0 normally this is not a problem because you could have a camera that is +2 and a lens that is -2 so they cancel each other out to 0 or they both could be +2 which would still keep you within tolerance at +4. The problem happens when you come across a combination that is higher then + or -5, so your 7D and bare lenses could fall within the tolerance ranges but when you add the TC you cross it. This is the main reason Canon added the micro adjust feature to their cameras and why you should test both the bare lens and the lens with the TC added. I am not saying this is the problem you are experiencing just that it could be.Quote:
Originally Posted by Christopher C.M. Cooke
Respectfully,
Don
well this explains everything here to not go for 7d if wish to use 2x for some long range records :) better wait for 5dm2 budget :)
thanks a lot friends
Mital bhai, a 7D with 500 and 1.4 TC will give you slightly more reach than 5d mkii with 500 and 2x TC. 5D MKII will not AF with 2X either.Quote:
Originally Posted by mitalpatel
Sorry mate but Arash is right, sell the kids off for medical experiments and put the cash into a 1D MKIV:):)
HI Mital, 7d will do autofoucs in live view only with 500/f4 +2x, but yes it will be very slow. It is usable mostly for stationary and extremely slow moving subjects.
Both TC's were redesigned in 2001. The 1.4x TC got a weather seal to mate with the sealed lenses and additional multi-coatings to internal surfaces. The 2x TC was completely redesigned (including weather seal) and is slightly sharper that the original design. I suspect the lens TC combo you tried needed a micro adjustment to obtain maximum sharpness.Quote:
Originally Posted by Alfred Forns
A friend and I tried his 600 f4L +Canon 1.4TC on my 7D and his 5D MkII. The AF was faster on the 7D by a decent margin and the light was very marginal, flat and grey. The image size in the viewfinder was a big change between those two cameras. The image with that lens has a field of view equal to a 1300+mm lens.
I know that wasn't the exact question, but it demonstrates an combo that works very well.
Dave
That's probably the reason why Canon discontinued the Extenders on the US website.Quote:
Originally Posted by Christopher C.M. Cooke
Both TC's are still available in the US. They are also listed as in stock at most major photo retailers. The Canon website probably doesn't show them as a lens, but rather an accessory.Quote:
Originally Posted by Pao Dolina
Reshuffling them about? Hmmmm could be but the Fox Mulder in me says... be wary of new white lenses before the Winter Games or World Cup plus extenders with Aspherical lens element like those on the new Nikon TC. :DQuote:
Originally Posted by Jeff Donald
When a product vanishes on the site it is either because they were discontinued with existing stocks being exhausted or an update is imminent.
Had no problem finding the TC's on Canons USA website
1.4 here
http://www.usa.canon.com/consumer/co...4&modelid=7462
2X here
http://www.usa.canon.com/consumer/co...4&modelid=7463
Mita,
The 5D Mark II will have the same limitations with a 500mm with 2x TC as the 7D. If you want true AF w/o live view you must use a 1D series camera.
Canon 1.4xTC II and 2.0xTC II are optical upgrades to the older versions and offer superior IQ. I would not recommend a non-Canon TC with a Canon lens.
The 7D with the 500mm + 1.4x TC and then cropping sharp images will yield superior results to a 7D + 500mm + 2x TC and soft images not cropped IMO.
I also found the 1200mm as well :) http://www.usa.canon.com/consumer/co...4&modelid=8178Quote:
Originally Posted by Don Lacy
I have been using the 7D with both the 1.4 EXII and the 2 EXII for a few months now (since the 7D came out and I haven't had any of the IQ issues I am hearing about on this board. It might vary from lens to lens, but micro AF could correct. Also, what is yor method of AF? Do you have the menu set to continuous AF? Are you using back AF? or do you AF using the shutter? Using single point AF? or all 19 points? Lens set to minimum focus range? All of these things as well as many others contribute to AF.....I think without knowing all of this information, it is impossible for people to say why you are experiencing these issues.
