Tele convertor

[henkbos]

Can anyone help me to get a convertor for 'old' lenses? Went to the store yesterday to find out the the current convertors do not fit with my older lenses (EF 28-80 and EF 75-300IS).

Does someone have experiene with the older and current convertors? There must be a reason why the design is so different (optical part sticking out an inch towards the lens).

Henk

[EugeneK]

I do not think that is has to do with age, but design. I have a brand new 70-300IS with the same problem. I have a canon 2X and a 1.4x and they both have optics sticking out too far. Most big fixed lenses have a hole for it (500 4.5L, 400is L). In a EOS system catalog they mention in the fine print which lenses they can be used with.
In the past I had used a tamron converter that did not have this problem with a 75-300 not IS.
Some bird photographers use large lenses with stacked 2X and 1.4X with an extension tube between them because the converters do not stack either.
Hope this helps some. -Eugene

[KHogan]

Hi Henk,

I was offered a great deal on a Tamron teleconverter (Tamron-F 1.4X teleconverter) so I've been playing with it on my various lenses. Among them, I own the 75-300IS and this teleconverter works just fine with this lens. In fact, it works without any problems on all my lenses. The Tamron teleconverters don't have the elements sticking out like the Canon converters do so you can use them on any lens (as far as I know).

If you want a higher quality teleconverter (the one I got is the cheaper version although I find that it does a great job and doesn't degrade the image), you can go with either the Tamrom SP series of teleconverters (which are the "pro" versions) or the Kenko Pro teleconverters (which, I understand, are the same units under a different name).

Hope that helps!
Kharim

[henkbos]

Thanks 4 the info. Do you loose funtionality when using other brands or do these brands use the same contacts on the mounting ring?

[EugeneK]

the 2X "Tamron-F AF tele-converter C-AF" does have the same type of connections, but not as many pins. Canon 2X has 8+3 pins and Tameron has 5+3 pins. This converter is about 10 years old. It seems to have the same functionality as the Canon, except it allows AF on big lenses, HOWEVER, the AF seeks a lot but has trouble getting a lock. Canon cameras disables AF when you get above a certain Fstop (lens and converter conbinations). This converter allows the AF, but its flaky. I tried the 2x with the 75-300IS and zoomed out it worked ok, but at about 200mm the focus started seeking and would not lock. The IS seems to work OK. When using the 2x on my old 75-300 non-IS lens I remember that I had to shoot MF.
My 500mm lense had the same problem with AF seek.
The Tamron 1.4 might work with AF with your lens. I recommend you try the pro converter and make sure you like the quality of the image. I do not like the quality of some of their lenses. Hope I helped. -Eugene

[chris maddock]

The last three pins that Eugene mentions are the ones used to impart the lens combination maximum aperture to the camera - hence TCs without them will allow the lens to try and AF even if the max aperture is smaller than the camera is designed to be able to AF at. Eugene's older TC will be one that does this. This can also be done by applying a bit of electrical tape over the last three pins on a Canon TC - it doesn't guarantee successful AF but, as Eugene says, the setup will at least try.

As Eugene says, the Image Stabilisation still works - it is not controlled by the camera at all(*), only powered by it. All the "wizardry" is contained within the lens, so any EOS compatible TC will not affect IS at all.

(*) not 100% true - some cameras will disable the IS if they are put into Mirror Lock-up mode, since that indicates to them that they are on a tripod, where IS should not be used anyway.

KRs
Chris