Tele-extender or cropping?

Started Oct 21, 2013 | Discussions thread
Doug Haag Senior Member • Posts: 1,525
Re: Tele-extender or cropping?

StevenMajor wrote:

You should test your equipment to learn what works best.

Since your concern is about sharpness, shoot the same static, detailed composition with and without the converter ( a flat brick wall works well parallel to the cameras sensor). Use a tripod and only change the shutter speed when using the converter. Treat both image files the same in post processing. Do a 2X crop on the non converter image. Judge both files side by side in Photoshop and you will have your answer.

Several years ago I did precisely this test with a Nikon 70-300 and a Tamron 1.4 converter ordered from B&H.  Because my 90mm f2.8 Tamron lens is sharper than any of my three Nikon lenses, I assumed it would be good glass.

Immediately following the test, I returned the converter because a crop of the same portion of the image taken without the converter was noticeably better than the same view with the converter.

And, yes, the camera was on a tripod and I held the f-stop constant (adjusting only the shutter speed) so that the f-stop would be the same.

Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow