Tele-Convertor / Extender

[hobo]

Recently purchased a Canon 90-300USM lens, which is perfect 90% of time for what I want it for.

The problem is the other 10% it doesn't quite reach far enough.

Having looked on the Canon website, this lens is not compatible with thier 1.4 & 2 extenders, so I wondered whether anyone knew of any it would be compatible with.

Don't want to spend a fortune as won't be used that much.

[V6GTO]

Believe me, the Canon extenders you mention are a fortune!

[hobo]

Could pick the 1.4 up for approx. £200, but as said they are not compatible with the 90-300USM lens.

Need something that is, for around (or less hopefully) this money.

[V6GTO]

Do'nt Jessops have anything?

[hobo]

Just spoke to Jessops, they said that the Canon Extenders would actually work with this lens but I would lose the auto-focus feature (would still be able to focus manually).

Does this sound right ???

They said no other way around it (apart from new lens £silly).

Just spoke to anothers Jessops branch who said that they do thier own brand convertor X2 for £76 which would manual & auto focus.

Arse & Elbow springs to mind.

>> Edited by hobo on Thursday 8th April 10:16

[simpo two]

hobo said:

Just spoke to Jessops, they said that the Canon Extenders would actually work with this lens but I would lose the auto-focus feature (would still be able to focus manually). Does this sound right ???

I was wondering about that as I read the thread. It just means (I think) that the autofocus system is not transmitted through the convertor. Manual focus is not a bad thing - if the object is a fixed distance away and not moving about too much, it's certainly worth considering. Even pros will use manual to prefocus on a spot and fire the shutter as the object passes.
I have a macro-focussing teleconvertor for my Nikon, and as it's not a Nikon part I lose AF too - but the benefits far outweigh the loss.

[hobo]

Cheers for reply, suspect I shall be heading to Jessops shortly to give thier own-brand convertor a blast.

The objects I would be photgraphing would be at a fixed length so manual focus would be fine.

[dcw@pr]

The reason that the Canon converter will not keep auto-focus is so that they can control the quality of the lens you put it on - it's the same with Nikons. They only make the tele-converters compatible with their expensive f/2.8 lens because if you use slower lenses you will have trouble getting a half decent aperture (f/5.6 on your lens will go to f/11 with a 2x converter), and therefore your pictures will probably not come out very well. Also, autofocus does not work well/at all below f/8, which is another reason they do not let you use them on slow lenses. Pretty much any 3rd party converter should be able to maintain autofocus, especially with a USM lens. Try Kenko as well.

[hobo]

Will do.

Thanks.

[ehasler]

There is a way of forcing the Canon converters to auto-focus with apertures of f5.6 and above - I'll have a dig around the archives and see if I can find the post, as it came up here a few months ago.

As far as I know, the Sigma converters should work just as well, and they are a bit cheaper.

[hobo]

Just had a look at the Kenko equipment.

Thier Pro300 teleconvertors are either, x3, x2 or x1.4

Can get x2 or x1.4 for approx £90 each.

Are these better than the Jessops own-brand models ? And would they fit onto the Canon EOS300 SLR ?

[ehasler]

Here it is:

www.fredmiranda.com/TipsPage/index.html

[hobo]

Thanks a lot for responses.

Have just come across the Kenko Extension Tube Set (3 Different lenses which can the matched to suit requirements).

This sound exactly what I want.

Problem now is I cannot seem to find anywhere in UK that sells them (doing search on YAHOO).

HELP !!!

[simpo two]

hobo said:

Problem now is I cannot seem to find anywhere in UK that sells them

You could try www.srbfilm.co.uk. It's a small engineering company that tailor-makes anything to fit onto anything. Worth bunging them an e-mail to see if they can make you an extension tube to your requirements.

Though hang on, does a lens fitted to an extension tube still focus to infinity? I think of them as a close-up device.

[dcw@pr]

hobo said:

Thanks a lot for responses. Have just come across the Kenko Extension Tube Set (3 Different lenses which can the matched to suit requirements). This sound exactly what I want. Problem now is I cannot seem to find anywhere in UK that sells them (doing search on YAHOO). HELP !!!

Hold on!!!! An extension tube IS NOT THE SAME THING as a teleconverter! An extension tube is just a tube filled with air, whereas a teleconverter is effectively a magnifying glass. Extension tubes are for macro photography. To be on the safe side find the product you want in a shop, try it out there, take some photos and see the results back at home. Then have a look on the internet for that product, which will hopefully be a lot cheaper. Try eBay.

[hobo]

Ending up buying a Kenko Pro300 x2 Teleconvertor.

Cheers for all advice.

[murph7355]

But if you're going to use this tactic, at least give the shop the chance to get closer on price.

If everyone did this, the shops wouldn't last very long and we'd all be buggered.

I don't own a shop, or know anyone who does. And I hate being ripped off as much as the next man, but we have to make sure we don't shoot ourselves in the foot.

[david010167]

Just to add to this thread.

The canon tele converter (extender) protrudes into the lense you add to the convertor, because of this it will not work with all lenses that have lens elements close to the mounting ring. It does also reduce the light to a degree that could stop the AF from working, however I do believe it is the problem that the convertor could foul on the rear element of the mounted lense.

David

[dcw@pr]

david010167 said:

The canon tele converter (extender) protrudes into the lense you add to the convertor, because of this it will not work with all lenses that have lens elements close to the mounting ring. David

By and large this is only a problem with wide[r] angle lens. The rear elements on long focal length lens should have a fair amount of air between them and the lens mount. Obviously using a wide angle lens with a teleconverter is not a usual occurence, so it shouldn't be too much of a problem.

[david010167]

Good point, a convertor and a wide angle is not a good thing I must check but I think it also fouls on the 28-135 IS lens as well, but that may be bad memory.

David