Teleconverter

[Beh162]

Could you put a 2x teleconverter on a canon 85mm usm lens?

Would that mean I'd go up to f/2.8 when using it?

[Ads]

[O|||||||O]

They will only fit certain lenses. Basically only the white L's.

[dxqcanada]

Check the Canon docs: Canon U.S.A. : Consumer & Home Office : Extender EF 2x III for compatibility.

[Patrice]

Check the Kenko TelePlus Pro series. They are chipped and because they don't intrude into the lens rear housing they tend to work with nearly all focal lengths. With 2x converter your field of view will be reduced to that of an 170 mm lens and you will loose two stops of aperture.

[SCraig]

Check the Kenko TelePlus Pro series. They are chipped and because they don't intrude into the lens rear housing they tend to work with nearly all focal lengths. With 2x converter your field of view will be reduced to that of an 170 mm lens and you will loose two stops of aperture.

Plus a LOT of image quality. My 1.4 isn't bad and I use it quite a bit. My 2x is horrible and never gets used for anything.

[AndySplash]

I use my 2x Extender III on my Canon EF 70-200mm f/2.8L IS II USM - yes I lose two stops but with no degradation whatsoever to the image quality. Awesome kit that marries up quite nicely

[gryphonslair99]

I use my 2x Extender III on my Canon EF 70-200mm f/2.8L IS II USM - yes I lose two stops but with no degradation whatsoever to the image quality. Awesome kit that marries up quite nicely

Funny, I use my EF 1.4X III or EF 2X III on my 70-200mm f2.8, 300mm f2.8 or 400mm f2.8 I do experience image degradation. Not bad enough that I can't use the images, but there is degradation. Less with the 1.4 than with the 2X.

To the op. Telextenders are designed for 100mm and above and for top of the line glass. Keep in mind that a telextender will provide a magnification of what the lens sees. It will also magnify any issues or optical defects with the lens as well.

If you want to try something like the Kenko, I would suggest that you go to a camera shop with your body and 85mm lens and take a few shots with the Kenko attached and see if the IQ meets your standards.

[Overread]

Far as I know Kenko have the smallest front element protrusions in the teleconverter world; there are also at least 2 kinds of Kenko teleconverters; low end and high end. For teleconverters you'll always want to go with the latter.

I'm not sure if the 85mm will fit any teleconverter and I'd suspect that you'd be better set to consider investing in some native longer focal length lens(es).

I use my 2x Extender III on my Canon EF 70-200mm f/2.8L IS II USM - yes I lose two stops but with no degradation whatsoever to the image quality. Awesome kit that marries up quite nicely

It's a fantastic combo - but like gryph - I do indeed see degradation of the overall quality with the 2*TC (in fact I don't think there is a lens out there that won't show some drop in overall quality with the 2*TC added). However it is minimal (with the 2*TC I find f7.1 more usable than wide open at f5.6) and very workable, esp once processed for output.

[AndySplash]

Okay maybe I was exaggerating just a little. At the end of the day the loss is minimal and not worth worrying about when compared to the gain by having it attached. The extender with the lens is a damn good match and works extremely well together. I certainly wouldn't leave in my bag and not use it.

[Beh162]

Oh okay thanks! Wasn't sure if you could use a teleconverter on lenses below 100mm

[KmH]

Teleconverters (TC) decrease the effective maximum aperture of a lens. A 2x TC causes a 2 stop loss of effective aperture

A 2x TC on a f/1.4 lens makes the effective maximum aperture f/2.8, even though the lens aperture is set to f/1.4.

[SCraig]

Teleconverters (TC) decrease the effective maximum apereture of a lens. A 2x TC causes a 3 stop loss of effective aperture

A 2x TC on a f/1.4 lens makes the effective maximum aperture f/2.8, even though the lens aperture is set to f/1.4.

My 2X teleconverter causes a 2-stop loss of aperture, not 3 stops. OK, your second sentence does show two stops, I missed that at first.

[TheBiles]

Canon TCs are for L primes 135mm and up, plus the 70-200s and 100-400.

[KmH]

Teleconverters (TC) decrease the effective maximum apereture of a lens. A 2x TC causes a 3 stop loss of effective aperture

A 2x TC on a f/1.4 lens makes the effective maximum aperture f/2.8, even though the lens aperture is set to f/1.4.

My 2X teleconverter causes a 2-stop loss of aperture, not 3 stops. OK, your second sentence does show two stops, I missed that at first.

My bad. Typographical error and ineffective proof reading.

[TCampbell]

I sometimes use the Canon 2x adapter on my 300mm f/2.8L IS prime. It does technically cause some image quality degradation but it's not noticeable in the average image unless I do a 100% crop such that you can see the fine detail.

The 85mm USM is an f/1.8, not an f/1.4. So a 2x adapter would bump that up to an f/3.5. When you use an extender you multiple both the focal length and the focal ratio by the teleconverter's factor (whether it's a 1.4x or a 2x -- so 1.8 x 2 is 3.6 but all focal lengths and ratios listed on lenses are rounded. Even f/1.8 isn't technically accurate... it's a rounded value. The nearest third stop after doubling the focal ratio is f/3.5)

Alas... it doesn't matter because the 2x adapter isn't compatible with that lens. You can see the compatibility list here: http://gdlp01.c-wss.com/gds/8/030000...-2x-iii-en.pdf