300 mm + 1.4 teleconverter

[KeithB]

I have the Canon 70-300mm telephoto soom, and I am going to Florida in a few months. I want to get good images of gators and things (but I don't want to get too close!). I also have a Tamron 1.4 teleconverter.

So should I stick with the lens by itself or add the teleconverter? I did the quick test test that Bob laid out with the test patterns in the center and corners, and found that, yes, you really need a calm day and tripod for that test. 8^)

It was pretty clear that there is more chromatic aberration with the converter. (If you use the white pegboard for Bob's test, the holes make for a good CA test pattern).

I remember from Bob's article from way back that it is kind of a wash, so I was looking for any more thoughts or suggestions.

[Bob Atkins]

When I did the test of the 70-300IS I found that center resolution was better with the 1.4x than upsizing the image without the TC.

See http://www.bobatkins.com/photography/reviews/ef_70_300is_review.html for an example

AF may be either non existent or flaky, depending on the camera, but that's something you can test before you go on the trip. You might get AF at f8 on an APS-C body by using contrast detection in Live View. It's worth testing.

Personally I'd probably shoot some shots at 300mm, then add the TC for a few more shots if I had time. That way you get to pick the shots that work out best.

[KeithB]

Actually, my AF seems to work fine. But thanks for the other suggestions, I will take the 1.4X and try to take some comparison shots. I think the main problem with sharpness is that the IS won't be as effective at 1.4X, so bright sunny days will be the ticket.

[Bob Atkins]

You're in luck with the AF then! The IS will work, but the camera will think it's a 300mm lens and so it won't be using quite the right stabilization parameters. Should be better than no IS at all though. A tripod would be the best support option of course, even a lightweight travel tripod (or monopod). I use my Velbon 343e travel tripod quite a lot (see review below). It's no longer available, but there are similar options out there.

http://www.bobatkins.com/photography/reviews/velbon/velbon_343e.html

[bmpress]

I just got back from a photo trip to the Everglades National Park near Homestead and can say that gators are numerous in natural locations where you can shoot pics as close as ten feet. I used a 70-200 and never needed more reach. I was always safe.,  but if you choose to walk in wild locations near water you put yourself at great risk.   

[KeithB]

Thanks, bmpress.

For reach, I was thinking more in the terms of bald eagles, not gators. Did you see anything else?