Canon 70-200mm f4L +/- 1.4x Extender Test

dugnsuz (Doug) · #1 10-04-2008, 12:54 AM

Hello all...
As promised, a side by side performance of the Canon 70-200mm f4L lens with and without the Canon EF 1.4x Extender.

Both Pics - iso200 @ f5.6, single 10 minute exposures, Canon 40D.

Pic #1 Eta @ 200mm
Pic #2 Eta @ 280mm (with 1.4x extender)

(Taking 1.6x crop factor into consideration, in reality 280mm and392mm FL)

File compression has lost critical detail, but there seems to be very little degradation in image quality with the addition of the 1.4x extender.
On close inspection of the uncompressed TIFF files, there was a slight softening of stars at the extreme edges of the field - but not worth worrying about. No increase in CA either

Very impressed - nice solid feel when attached to the camera too.
Hope this helps some.
All the best
Doug

ps...there's a 70-200mm for sale in the trade section right now if anyone is interested (not mine!)

Garyh · #2 10-04-2008, 10:08 AM

Very nice results Doug! My poor old cheapy 2x telextender is not quiet up to astrophotography but that is a fine result with the canon 1.4x one.
Might make a nice chrissy present for me

...hint hint my gorgous wife!

cheers Gary

dugnsuz (Doug) · #3 10-04-2008, 10:19 AM

Quote:

Originally Posted by Garyh

Very nice results Doug! My poor old cheapy 2x telextender is not quiet up to astrophotography but that is a fine result with the canon 1.4x one.
Might make a nice chrissy present for me

...hint hint my gorgous wife!

cheers Gary

Good Luck

Compression has made pics look blocky and pixelated but hopefully they show that the 1.4x Extender does a good job.
Doug

davewaldo · #4 10-04-2008, 10:28 AM

Good results, One thing to bear in mind, is that the lens would have been stopped down more when not using the extender than when you used it.

Basically by shooting both frames at f5.6, when you didn't use the extender the lens was stopped down one stop. When you added the extender the lens would have been wide open (but with the extender giving you an aperture of 5.6).

So a better comparison might be to shoot an image on f4 with no extender and compare those results.

I think this is correct... what do others think?

Dave.

leon · #5 10-04-2008, 11:00 AM

Good result Doug, for a single exposure, get a few of those together and you will be laughing mate, nice work.

Leon

dugnsuz (Doug) · #6 10-04-2008, 11:19 AM

Quote:

Originally Posted by davewaldo

Good results, One thing to bear in mind, is that the lens would have been stopped down more when not using the extender than when you used it.

Basically by shooting both frames at f5.6, when you didn't use the extender the lens was stopped down one stop. When you added the extender the lens would have been wide open (but with the extender giving you an aperture of 5.6).

So a better comparison might be to shoot an image on f4 with no extender and compare those results.

I think this is correct... what do others think?

Dave.

Cheers Dave,
I get what you mean, but this was only really a rough quality test.
Just wanted to see that there would be no substantial loss in quality with the extender attached.
Cheers
Doug

davewaldo · #7 10-04-2008, 11:42 AM

Well you certainly proved both the lens and the extender have great optics! Its made me want to have more of a play with my 70-200F4L

Thanks for posting the images