Extender tubes

[NimArt]

<p>Hi every one<br>

I have a Canon 7D with 70-200Lf4 lens, and I just wanted to know about the extendertubes, witch are x1.4II and x2II and as you know in x1.4 I lose 1 stop and x2 lose 2 stops.<br>

But I want to know despite of losing two stops in x2, do I lose the quality in the picture as well? and which one is better than the other one? x1.4 or x2 ?<br>

I just want to know how is it to use teleconvertors? many thanks for your answers.</p>

<p>thank you in advance<br>

Nima</p>

<p> </p>

[robin_sibson1]

<p>You are in danger of confusing extension tubes, which are glassles spacers between body and lens used fo close-up work, and teleconverters, called Extenders by Canon. You are clearly interested in Extenders <strong>not</strong> extension tubes. The terminology "extender tubes" is not used.</p>

<p>You do not say if your lens is the older non-IS or mre recent IS version of the 70~200/4L. With the Extender 1.4× II you will get reasonably good results with the non-IS version and very good results with the IS version; phase-detect AF will still work on any Canon EOS body, but will be slower. With the Extender 2× II you will lose quite a lot more image quality, to the point where you would probably do better to use the Extender 1.4× and crop, and you will lose phase-detect AF except with 1D-series digital bodies and the EOS-3 and EOS-1V film bodies, which will still provide phase-detect AF at the central focusing point. If you have an EOS DSLR with contrast-detect AF in Live View, that will still work with either Extender.</p>

[dcstep]

<p>Your talking about Teleconverters, not Extension Tubes. Use the Canon brand for the best results and correct recording of EXIF data. I regularly use my 70-200mm f/4L IS with an EF 1.4x TC with great results. Technically there is slight reduction in IQ, but the end results are excellent.</p>

<p>The EF 2x TC will not AF on the 7D with an f/4 lens. You might use it for macros and MF the lens, but for other uses it'll be frustrating. You'll lose slightly more IQ with the 2x and, as mentioned, you might do as well by using the 1.4x and cropping. The first reviews of the new Series III 2x do indicate substantial improvement in the IQ over the series II, but it'll still have the AF limitations.</p>

[NimArt]

<p>Thank you Robin, thank you very much and you are right, absolutely right, but it was a mistake, a mistake on words, sorry.</p>

<p> </p>

[NimArt]

<p>Thank you David for your nice comment on my question,I am deciding to purchase the x1.4 one.<br>

thank you</p>

[joseph_wisniewski]

<p>This is a heretical viewpoint. There's some loss of optical quality from a 2x teleconverter, but most of the bad rap that they get is because people have no idea how to deal with the "effective" long lens that they get from using a teleconverter.</p>

<p>You've got a 70-200 f4 on a 1.6x crop camera. That's already effectively 112-320mm. Put it on a 2x TC, and it's now a 224-640mm f8 lens. 640mm is a really long lens. Remember the old 2 pounds per 100mm rule of picking tripods? A 320mm lens might go on a 6 pound tripod+head, like a Bogen aluminum 055 + a pistol grip ballhead, but that won't hold a 640mm steady. You'll get soft shots just from breezes or the camera mirror mechanism vibrating the camera and tripod.</p>

<p>Unless you go to the trouble of using "long lens techniques" like draping a beanbag over the lens to act as a damper, using mirror lockup, and using a really heavy tripod, you're not getting sharp shots out of any telephoto on a 2x TC.</p>

[dcstep]

<p>If you take Joseph's view, then even the 1.4x TC would be equivalent to over 500mm. Yet, I seldom put mine on the tripod and handhold (mine has IS) my 70-200mm with the 1.4x TC with no difficulty at all getting sharp images. I don't think moving up to the 2.0x TC is the real problem. Test shots on tripods show the Series II 2.0x to have poorer image quality than the 1.4x.</p>

<p>You DO need to be aware that the lens is longer and you need to use higher shutter speeds. If light demands a slower shutter speed, then a tripod or bracing may be appropriate. Now that I rountinely hand hold my 500mm f/4L IS with and without the 1.4x TC I find that it's important to be aware that you've got a long lens, but all that weighting, extra damping, mirror up, etc. just doesn't work when you're shooting sports and wildlife. When I shoot at low shutter speeds on a tripod, I do damp the lens with my left hand, but that's about all and I've gotten some really nice shots as slows as 1/100th second at an effect focal length of 1120mm. (My tripod, ballhead and Wimberley Sidekick are very sturdy).</p>

<p>Back to the 2.0x TC, you need a native f/2.8 lens to use AF on the 7D, so that's the real reason to avoid it, unless you have special uses where MF will be practical.</p>

[NimArt]

<p>Joseph and David thank you very much for you nice and usefull comments on my question.</p>