TC Musings

[robski]

My normal telephoto setup is a Canon 300mm f4 IS plus the option to add a Canon 1.4 TC. The raw lens gives very good results and adding the 1.4 TC still gives very acceptable images. For sometime I've had an itch that needed scatching to see how well a 2.0 TC would work. My local photography shop had a Canon x2 instock and I could not resist the temptation anymore. I bought it on condition if it was a flop I could return it. Needless to say I returned it the next day. But I had it long enough to do a quick and dirty test. Shots of a sawn tree stump but alas the wind was starting gust. However I have posted for your amusement.

1) Raw lens
2) 1.4 TC
3) 2.0 TC
4) 1.4 + 2.0 stacked
5) first image upsized in PS by 2.8 to compare against fourth image.

dragging off image 1 and progressively enlarging it to compare it alongside 2-4, it looks as if you are better off doing a more severe crop from just the basic lens. The converters appear to introduce chromatic abberation without any more detail.

Or isn't that what I am supposed to say/find?

If it is you have saved me another £140-180 (temptation, no money anyway) getting TCs for my Sigma 50-150

[Dave Smith]

Very interesting Rob. I hope you don't mind but I have increased the first one by 1.4x to compare with the second. The left picture is your first increased and the right the one with the 1.4x TC

It would appear that the 1.4x doesn't do much either. I have a 1.4x so will carry out some further tests when I have time.

Dave

[Don Hoey]

A good thread subject Rob as this is something a lot of people think of to increase focal length on a budget.

I found similar results when using a 2x with the 80-200, and that was a sharp lens when used on its own, hence the reason for swapping it for a straight 400mm.

Rubbish weather this week so I have time to think of a target as I don't have a sawn log end handy. Then I will see if I can post some comparison shots with mine and a couple of lenses.

Don

[Don Hoey]

I thought I ought to post a link to Andys site with some TC info http://www.digiscoped.com/teleconverters.html

Don

[Dave Smith]

This one has me hooked. I couldn't wait to have a try.

Here I was using a 200mm EF 2.8L lens with and without a 1.4x TC (Canon).

The left picture is just the 200mm lens but the image enlarged in PSPX by a factor of 1.4 and the right image is with the 1.4 TC.

Anyone want to buy a TC? Perhaps I will do some more tests before I do that, but it looks as if money could have been saved here.

Dave

I should add, they are both 100% crops.

[Leif]

Originally Posted by Dave Smith

Here I was using a 200mm EF 2.8L lens with and without a 1.4x TC (Canon).

Teleconverters tend to work better with some focal lengths and some lenses than others. I suspect the Canon ones are optimised for use with long lenses, and that the 200mm lens is ill matched. That is consistent with the fantastic results Andy (and others) get with a TC and a 600mm lens. Nikon even had two teleconverters, one for long lenses, and the other for not so long lenses.

[Don Hoey]

Another link on the subject, although these are comments on Nikon converters. http://www.naturfotograf.com/index2.html

Click on lenses on the left hand index, then scroll down to the bottom of the page for Teleconverters.

Don

[Don Hoey]

I will have a go when the hail, sleet and snow packs up.

Don

[Dave Smith]

Originally Posted by Leif

Teleconverters tend to work better with some focal lengths and some lenses than others. I suspect the Canon ones are optimised for use with long lenses, and that the 200mm lens is ill matched. That is consistent with the fantastic results Andy (and others) get with a TC and a 600mm lens. Nikon even had two teleconverters, one for long lenses, and the other for not so long lenses.

Thank you for that Leif. I will next test it with my 100-400 lens.

Dave