t4i and 1.4 extender

[sedwards]

ive been reading a lot of reviews on line and cant really find a true answer. some say to put tape on some of the pins but the canon website says in wont work on my camera. has anyone used one on a rebel series camera if so how bad is it when they say autofocus is slow ? ill be getting a new lens in about a month , either a 300f4L or 400f5.6 and im thinking of an extender for a little extra reach for when the critters are a little far.

[neuroanatomist]

The camera isn't necessarily the issue. It's more the lens, and the max aperture of the combo. A 1.4x TC costs 1-stop of light - an f/2.8 lens becomes f/4, an f/4 lens becomes f/5.6, an f/5.6 lens becomes f/8. A 2x TC costs 2-stops - an f/2.8 lens becomes f/5.6, f/4 becomes f/8, etc.

Your camera is needs an f/5.6 lens or faster for phase AF (viewfinder) to work (live view works to f/11 at least). The 1D X and 5DIII can AF with an f/8 combo, although only with the central point with 4 expansion points.

So, you can use a 1.4x TC with an f/2.8 or f/4 lens on your camera and still have AF. Note that I'm referring to max apertures, it doesn't matter what aperture you select for the shot (AF is always done with the lens wide open). The 300/4L + 1.4x (II or III) gives a very good 420mm f/5.6. The 400/5.6 + 1.4x is an optically decent 560mm f/8, which won't AF on your camera (it will on the 1D X/5DIII). You get better results whenever using a TC with a non-supertele if you stop down from max (300/4L + 1.4x shot at f/8).

The other issue is that with the Canon TCs only certain lenses are physically compatible. The TCs have a protruding front element, and the lens needs space for that. Only a subset of L-series lenses work with Canon TCs - zooms starting at 70mm and longer (except the 70-300L, which is technically partially compatible but don't go there), and primes starting at 135mm.

If you use a 3rd party TC (e.g., Kenko), they are physically compatible with any EF or EF-S lens, but the optical results may not be worthwhile (although the Kenko 1.4x DGX Pro with the 100L macro, results are decent; with the 70-300L, too, but that combo won't AF on your body).

Hope that helps...

[sedwards]

that helps a lot. basicaly the the 400 5.6 would become a f8 and not autofocus . f8 probably wont work for me anyways as i do a lot of wildlife shots at the end of the day and cant push the iso real high without loosing image quality. im probably gonna go with the 400 5.6 but the is of the 300f4 has me thinking hard about it. i had a cheaper 75-300 for a while and it was a bit short . i wish i was rich , i would buy them both and a 5dmrkIII lol. thanks for the explination.

[neuroanatomist]

The problem you'll run into with the 400/5.6 is without IS and on a crop body, unless you're shooting from a tripod you'll likely need 1/800 s to avoid blur due to camera shake, and that probably means a high ISO anyway. THe 400/5.6 is considered a BIF lens, because for that application you need a fast shutter no matter what. The IS on the 300/4 is only 2-stops, but with a 1.4x TC that means you can be down around 1/200 s and still get sharp shots when handholding (of course, that won't work if your subject is moving with any alacrity).

[clemmb]

The problem you'll run into with the 400/5.6 is without IS and on a crop body,
The IS on the 300/4 is only 2-stops, but with a 1.4x TC that means you can be down around 1/200 s and still get sharp shots when handholding (of course, that won't work if your subject is moving with any alacrity).

I would go with the Canon EF 100-400mm f/4.5-5.6 L IS USM, It is sharper than the 300 + 1.4 and has IS. A few more buck$ but not much.

[sedwards]

interesting point . 1/800 wont work to well at last light lol . i could probably use a tripod for most low light stuff as it is usually deer feeding and they dont move around much. ill mull it over till the time comes to buy one. there isnt a huge difference in price between the 2 or the choice would be easier.

[Dave Throgmartin]

IMHO buying lenses with the plan to use teleconverters will just end in disappointment.

Dave

[peety3]

IMHO buying lenses with the plan to use teleconverters will just end in disappointment.

+1. Just crop the final image and be happy with it.
See http://www.lensrentals.com/blog/2009...converters-101

Also take a look at item 5 in http://www.lensrentals.com/blog/2010...-the-whole-set

[conropl]

Also take a look at item 5 in http://www.lensrentals.com/blog/2010...-the-whole-set

#6 makes sense also.

Stuart - I do not think anyone answered your question about taping the contacts when using a TC. I have tried it with my 100-400 L with a 1.4X II TC on a 7D (which I would guess should be better than your rebel), and it performed horribly. If you want to increase your frustration level with missed shot after missed shot while you are waiting for the focus to acquire, then it is a way to go... or you could just put it in live view and auto focus with the little box (even have the option of 5X and 10X focusing) without the tape and still achieve focus almost as fast as taping contacts. I am not sure how it would perform with the 400 mm prime, but I would guess it would have similar results.

The other problem with TC's on a camera that does not have good high ISO capability is the light seems to always be to low to get a decent shutter speed (the problem I had with the 7D focused using LV... auto or manual). I finally made the jump to FF with a 1D X, and I am really loving the ability to set my ISO at 1250 to get my shutter speed faster that 1/1000 sec. The bad part is I miss the 7D crop factor... so the 1.4X TC lives on my 100-400 mm most of the time. However, because I now have the ability to get shutter speeds up with higher ISO, it outperforms the 7D (even if I crop some). I very seldom produced an acceptable image with my 7D with the TC/100-400 combo, but I regularly do with the 1D X; and I attribute much of that to being able to get the shutter speed up. Which is also the reasons why neuro was pushing the IS need.

I wish a 600 mm f/4 L IS II was in my future, but that is not likely.

[Jayson]

I would agree with Mark. If I had to do it all over again I would have purchased the zoom. I was in your same spot 3 years ago and went with the 300mm. I use a kenko tc on it almost all the time because it just wasn't long enough. The reason I went with the 300mm was more for its closer minimum magnification. You can toss the tc in and you have a great semi macro for little things and you get plenty of working space. I enjoy taking photos if little things but I am about the only one who likes the photos. If your in a place that's sunny most of the time the 400mm prime will be fine. I would look at the refurbished store and get the zoom when they have their discount and I'm sure you'll be very happy.