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lens converters?
Can someone explain what a lens converter is, why would I need one, is it just a "Mickey Mouse" way to get a telephoto lens (for instance), and can I use one (use them) on a Canon 300d?..

Comments (14)

Are you talking about those screw on dealies? Those are mickey mouse, just about the same as holding a magnifing glass in front of the lens. A teleconverter fits between the lens and the camera is a good way to extend a tele to a longer tele. Those aren't suppose to be used with shorter fl lens.

Image control:Zoom outZoom 100%Zoom inExpand AllOpen in new window..

Comment #1

It fits between the lens and the camera body. It extends the focal length of the lens in use, and contain glass elements. Most are 1.4X or 2X types (converting a 200mm lens to a 280mm or 400mm respectively) and will cost you 1 to 2 stops of light respectively. Some slight image degradation is expected, mostly noticeable on the 2X..

They most certainly are not "mickey mouse". the decent models can cost up to 500 bucks each; that being said, some models like Kenko are much cheaper, but the quality stinks. Many pro football photographers routinely use a 1.4X converter coupled with a 400mm f/2.8 lens..

Yes, they'll work on a 300D, but not with EF-S lenses. Don't even try, will be a very expensive mistake. They are primarily designed for longer that normal focal length lenses. They will fit shorter length lenses as well, but as far as the image quality goes, they are not meant to be on these lenses...

Comment #2

The quality of some screw on converters are truly excellent. But they do not work to well with DSLR cameras..

On Bridge cameras Wide Angle and telephoto screw on lenses work extremely well - and give respectively a wider field of view, or a zoomed/magnified image.. Also screw on macro lenses work well - they 'convert' the focus distance on an existing lens. BUT - only ever buy the very highest quality achromatic ones!.

Adrian.

Http://www.t1000.co.uk/photography/gallery1/ (New Gallery)http://www.t1000.co.uk/photography.htm..

Comment #3

Thanks, y'all! That makes perfect sense. So I don't want to waste my $$, right?.

This is my first DSLR. I have a Sigma 28-105 MM lens. I'd like something better (maybe telephoto -telescopic(?) like the Canon EF 100-300mm f/4.5-5.6 USM), but I only have about $300..

I'm real rookie. I don't really know why I think I want that model. I think I'd like something that can take pictures of things far away or zoom in really close..

Am I on the right track? Any thoughts?..

Comment #4

I'm having trouble finding information on lens converters. Maybe I'm just not Googling the right words. Do any of you know where a real rookie can find layman information on converts?..

Comment #5

Harrybutts wrote:.

This is my first DSLR. I have a Sigma 28-105 MM lens. I'd likesomething better (maybe telephoto -telescopic(?) like the Canon EF100-300mm f/4.5-5.6 USM), but I only have about $300..

So then go buy one, it's a $300 lens. Forget about sticking a teleconverter behind your current lens, you'll lose auto-focus and image quality will be horrible..

And say hello to Bart..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #6

Here is the info for Canon's 1.4x teleconverter (they call it an extender for some reason)..

Http://www.bhphotovideo.com/FrameWork/charts/canon1_4xExtender.html.

Http://www.bhphotovideo.com/...56-USA/Canon_6845A004_1_4x_EF_Extender_II.html.

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Comment #7

Not all screw-on teleconverters are bad. Here's an example of an Olympus TCON-17, about $90 on eBay..

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These are 100% crops, hand-held. Identical ISO, exposure time, etc..

The advantage of the screw-on tcon's is there is little light loss. The front element of the Oly TCON-17 (or B-300) is about 75mm..

For the lens pair shown in the example the f/2.8, 135mm lens is effectively changed to a 230mm, f/3.0 lens..

There is some increased flare due to the extra surfaces, but it can be removed in PP if necessary...

Comment #8

Dave Martin wrote:.

Image control:Zoom outZoom 100%Zoom inExpand AllOpen in new window.

These are 100% crops, hand-held. Identical ISO, exposure time, etc..

A coke bottle looks good at f/8. Why not show f/2.8?.

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #9

F/8 is the example I had on hand..

I think it shows that screw-on teleconverters aren't necessarily terrible..

Earlier postings implied they had no value...

Comment #10

Dave Martin wrote:.

I think it shows that screw-on teleconverters aren't necessarilyterrible..

Agreed..

Earlier postings implied they had no value..

They have the greatest value on fixed lens cameras because there is no other choice. On a DSLR you have a lot more options..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #11

Nickleback wrote:.

Dave Martin wrote:.

I think it shows that screw-on teleconverters aren't necessarilyterrible..

Agreed..

Earlier postings implied they had no value..

They have the greatest value on fixed lens cameras because there isno other choice. On a DSLR you have a lot more options..

I only tried the TCON on the DSLR because I had it already for a fixed lens camera..

I was surprised it worked as well as it did..

I'll try it at f/2.8 & report back...

Comment #12

The following 100% crops were taken with a Canon 300D & 135mm 1:2.8 SF lens. ISO400, 1/400 sec. The shot without TCON-17 was at about 3 meters from the subject and the shot with the TCON-17 was at about 5 meters..

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The Canon 135mm SF is a reasonably sharp lens (about 1750 lw/ph), see:.

Http://www.photozone.de/.../359-canon-ef-135mm-f28-sf-lab-test-reportreview.

These are 100% crops of jpgs straight out of the camera. The focal plane and viewpoint for the two photos are slightly different; all-in-all I think the TCON combo is not bad..

The exposures were the same shutter speed & iso and appear pretty close, esp if you remove the TCON'as flare. That is, the TCON-17 didn't affect light collection much..

The 135 SF lens with TCON-17 is about like a 230mm, f/2.8 AF lens...

Comment #13

Dave Martin wrote:.

The following 100% crops were taken with a Canon 300D & 135mm 1:2.8SF lens..

Thanks for the test. BTW, that's a good bargain 135mm f/2.8..

The TCon shot has an obvious loss of contrast and detail..

The contrast difference is easy to see, even considering the slight underexposure thanks to f/3.0 effective aperture. Greens in the TCon photo are washed out and there is very little difference in saturation from one leaf to the next..

Detail loss is also evident, but it's a bit tricky to see because of the difference in the plane of focus. On the TCon image look at the leaf that the "finger" is pointing to, on the upper right side. On the non-TCon image look at the leaf to the next leaf on the right of the leaf looked at in the TCon image..

But OTOH, you've invoked my favorite 4-letter word that starts with "f". Since you already own the TCon, it's FREE. That's a good enough reason to use it..

Seen in a fortune cookie:Fear is the darkroom where negatives are developed..

Comment #14

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This question was taken from a support group/message board and re-posted here so others can learn from it.

 

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