Teleconverter vs Cropping the Picture?

I use a 2x iii on my 70-200 ii for wildlife w/ a 7d and can get the shutter speed up to 1/2000 or more at iso 1600 (which is perfectly fine on 7d) mid day and the results are very sharp.

The teleconverter will give more detail / sharper photo than simply crop into the same size:

http://www.the-digital-picture.com …r-EF-1.4x-III-Review.aspx
http://www.the-digital-picture.com …der-EF-2x-III-Review.aspx

Check on the gif photo.

I have used the 70-300L with the Kenko 1.4x on a t3i as well as the 5D3 and the results are not bad. Both will AF in good light. At 100 percent crop, I do see degradation of the 1.4x vs the bare lens. I'd use this only as a last resort.

The 1.4x with a sharper, faster lens like the 300f2.8 or 500f4 is fantastic.

Several telephotos (primes and zooms) combined with both TC's have been recently added to the Digital Lens Optimizer compatibility list in DPP.

Worth trying.

I did this comparison years ago.

First I'll show the full area of the frame when taken with the 70-200mm lens alone. You see that the crop area for the comparison is a small section of the entire frame.

But again, the 70-200 were designed for TC use.

tkbslc wrote in post #15579543
But again, the 70-200 were designed for TC use.

I posted the comparison because of Tom Reichner's comment "In my own experiences, using either of the extenders on my 70-200 f4 or my 100-400 . . . did not produce a desirable outcome. " I was simply showing what someone else's (my) outcome looked like, in counterpoint to that comment.

Wilt wrote in post #15575231
Optical solutions for 'magnification' are always better than those that resort to 'cropping pixels' (aka 'digital zoom').

Depending, of course, on the optical quality of the optical solution... Cropping is going to 1/2 the dimensions is going to better results than using a crappy TC.

Wilt wrote in post #15575560
Let us assume that a lens manages to capture 2500 line-pairs in the frame height.
Let us assume that a 1.4x convertor loses as much as 20% of the resolution
(photozone.de tests have shown that Canon 70-200mm lenses lost about 10% of resolution with Canon 1.4x teleconvertor, so we are being conservative in assuming 20% loss)

If you do 1.4x crop of pixels, we end up with 2500 / 1.4 = 1785 line pairs
If you do 1.4x optical magnification crop (teleconvertor), we end up with 2500 * 0.8= 2000 line pairs

One thing not mentioned here is the lost stop of light. Extra reach is often needed for action photography and to get the same action stopping shutter speed, ISO will need to be raised a stop to make up for it. In good light going from ISO 100 to 200 is no big deal. However if it makes you go from ISO 3200 to 6400, then that would be something worth thinking about.

I'd say the TCs were primary designed for the great whites

FEChariot wrote in post #15579648
One thing not mentioned here is the lost stop of light. Extra reach is often needed for action photography and to get the same action stopping shutter speed, ISO will need to be raised a stop to make up for it. In good light going from ISO 100 to 200 is no big deal. However if it makes you go from ISO 3200 to 6400, then that would be something worth thinking about.

Definitely! I often shoot the local Pro-wakeboarder in the summer, and he likes to get his practice in around 7:00-7:30 pm on. I start out with my 300/4L IS +1.4x, and by 8:00 or so, the light drops off.
As i'm shooting from about 400-500' away, i have to crop heavy, but prefer to drop the TC as the light drops, rather than go over ISO 640(60D). I have to crop harder at 300mm though, but the lower ISO balances out, but with useable shutter speeds.

londonbairn wrote in post #15579742
I'd say the TCs were primary designed for the great whites

The FAST great whites.

I did this experiment a year and a half ago with a live subject in a "real world" situation.

First are the full images, both with the "naked" 400mm and then with the 1.4 converter added. I tried to keep everything as similar as possible, with the only change being the addition of the 1.4 extender.

Now for the 100% crops, to show how well the detail was resolved.
First the one with the bare 400mm, then the one with the 1.4 extender:

Forget the results Tom. How were you able to shoot a deer with and with out a TC without him moving between shots? Or so it would appear. What are you freekin quick draw McGraw?