quick teleconverter question

[ovizii]

I am going to buy one and while browsing on ebay I found two types:

- screws in between lens and body
- screws on top of the lens

what are the differences and which one is recommended?
in my opinion without knowing anything about it I'd go for the one on top of the lens as it means all lens information is still properly transmitted through the lens contacts.

I have read up on teleconverters, I know I will be losing light, etc. I think I am quite well informed but I didn't know there are these two different types to consider.

would really be happy about some feedback from you guys...

[RecurrentNerve]

The one that screws on the end of the lens isn't strictly speaking a teleconverter, it's a macro filter; essentially a magnifying glass.

A true teleconverter is one that fits between the body and the lens.

The filter is generally cheaper and more convenient as you don't have to take your lens off to fit it. A set of teleconverters will give you more close-up ability.

[firebox40dash5]

Originally Posted by RecurrentNerve

The one that screws on the end of the lens isn't strictly speaking a teleconverter, it's a macro filter; essentially a magnifying glass.

^ This.

There is a reason teleconverters exist. If you could get the same results slapping a glorified magnifying glass on the end of your lens, Nikon, Canon, Sigma, etc. would be selling $400 magnifying glasses and not $400 teleconverters, and enjoying the extra profit margin.

Personally, I'd advise you to stop shopping for camera equipment on ebay. It's become little more than a venue for a million places in HK to hawk their cheap junk. Most of the desirable items I see are going for more than you could buy them for from a real camera store, let alone a reputable online shop like Adorama or B&H. If you know what you're looking for and its value, or it's a discontinued item, ebay can be great.

Back to your question- what camera/lens are you wanting to use this with? Kind of hard to answer any more than the obvious "a real TC is better" without that info.

[OsmosisStudios]

Originally Posted by firebox40dash5

Back to your question- what camera/lens are you wanting to use this with? Kind of hard to answer any more than the obvious "a real TC is better" without that info.

Quite interesting to find this out, yes.

None of Canon's EF-S lenses or NIkon's DX lenses accept TCs, and just about anything slower than f/4 cant either. Generally speaking TCs are only good on f/2.8 lenses.

[firebox40dash5]

Originally Posted by OsmosisStudios

Quite interesting to find this out, yes.

None of Canon's EF-S lenses or NIkon's DX lenses accept TCs, and just about anything slower than f/4 cant either. Generally speaking TCs are only good on f/2.8 lenses.

I know Nikon has the mounts of their new TCs designed to only fit with their f2.8 or f/4 AF-S tele lenses (and the 105mm Micro). I don't know for sure, but I thought the Sigma & Kenko TCs didn't have that 'feature', and you could at least try to make them work with lesser lenses? I can't tell with the Sigma, but the Kenko appears to keep the screwdriver AF functionality, which Nikon doesn't.

In theory, anything faster than f/4 should autofocus OK with a 1.4x, provided the lens elements of the TC and lens don't interfere, and you could always manually focus. Of course, image quality would be another question.

[ovizii]

That is what I have read too.
besides, my posts don't appear here...
if I simply reply, my post disappears, if I quick reply I get told its hold in moderation.
so if my answer makes it out of moderation, I'll take back my question about an alternative lens since I have found a good price/feature/comparison chart and realized how far outside my reach those lenses are :-(

[OsmosisStudios]

Originally Posted by firebox40dash5

I know Nikon has the mounts of their new TCs designed to only fit with their f2.8 or f/4 AF-S tele lenses (and the 105mm Micro). I don't know for sure, but I thought the Sigma & Kenko TCs didn't have that 'feature', and you could at least try to make them work with lesser lenses? I can't tell with the Sigma, but the Kenko appears to keep the screwdriver AF functionality, which Nikon doesn't.

In theory, anything faster than f/4 should autofocus OK with a 1.4x, provided the lens elements of the TC and lens don't interfere, and you could always manually focus. Of course, image quality would be another question.

The Nikon/Canon TCs are designed to only work with certain lenses, as you mentioned, and you are correct in assuming that the Sigma/Kenko TCs dont have that physical mounting difference, but they'll still interfere with the rear element of most DX/EF-S lens, regardless of whether it'll actually mount or not.

Originally Posted by ovizii

That is what I have read too.
besides, my posts don't appear here...
if I simply reply, my post disappears, if I quick reply I get told its hold in moderation.
so if my answer makes it out of moderation, I'll take back my question about an alternative lens since I have found a good price/feature/comparison chart and realized how far outside my reach those lenses are :-(

Your posts get put into moderation because you're new. That'll go away over time.

[firebox40dash5]

Originally Posted by OsmosisStudios

The Nikon/Canon TCs are designed to only work with certain lenses, as you mentioned, and you are correct in assuming that the Sigma/Kenko TCs dont have that physical mounting difference, but they'll still interfere with the rear element of most DX/EF-S lens, regardless of whether it'll actually mount or not.

Looking at them online, the Sigmas look the same as Nikon- the front element pokes out from the lens mount. The Kenkos look like their front (only?) element is actually recessed. Also, Sigma lists a good many small/variable-aperture tele lenses as being compatible with both their 1.4x and 2x TCs. But it's not like there are are any DX teles with a large enough aperture that you'd want to slow them down a stop or 2, even if they do fit.

I assume Nikon & Canon limited physical compatibility to keep people from trying to do something dumb like mount their 70-300mm on a 2x TC, and wonder why their AF doesn't work.

OP, to answer your original question somewhat: modern Sigma, Kenko, and Nikon/Canon teleconverters will all retain the electronic link between the camera and the lens. Whether they meter correctly (reporting the 'new' focal length and aperture correctly) and whether they autofocus (keeping the effective max aperture at least f5.6, and possibly keeping the physical 'screwdriver' link) would depend on your lens/TC setup.

I don't know for sure about older models of any of those brands, but I did try an old (manual focus) Nikon TC-14B with my 70-200mm... while it mounted fine, I had no aperture control with my D90 due to it being a G lens without an aperture ring. AFAIK, you'd need a lens with an aperture ring to have ANY functionality with an older TC, and likely still wouldn't have metering unless your camera allows you to input lens data manually.

If you're willing to buy an older manual focus lens and probably have to meter manually, you could get something cheap. But otherwise, yeah, it's gonna cost you a good bit to get a lens that will work well with a TC.