-=FAQ=- Teleconverter/T-Con Tele extender Discussion

Lester Wareham wrote in post #9612237
That is interesting Wilt, I had the opposite with the 200/2.8 and 300/4 IS.

Canon better on edge and the kenko sometimes better in the centre (this is on APS-C), have to say the difference was not great in the centre but larger on the edge and corner, generally I would recommend the Canon based on my results.

example SRF plots for the 200/2.8

You certainly have a much more scientific methodology, with graphs, than I did, Lester! I'll concede

I made up test charts using symbols found in Microsoft Word fonts, sized at increasing typeface sizes, printed onto paper and taped to the wall so that the symbols were located at Center, and also at Edge of frame, and I qualitative assessed the ability to distinguish fine detail to the smallest size differentiable (such as differentiating parallel lines of different sizes), but don't really have numeric data to back my observations.

Excellent graph Lester. SO the canon tcon is a better choice overall.

Wilt wrote in post #9615609
You certainly have a much more scientific methodology, with graphs, than I did, Lester! I'll concede

I made up test charts using symbols found in Microsoft Word fonts, sized at increasing typeface sizes, printed onto paper and taped to the wall so that the symbols were located at Center, and also at Edge of frame, and I qualitative assessed the ability to distinguish fine detail to the smallest size differentiable (such as differentiating parallel lines of different sizes), but don't really have numeric data to back my observations.

Thanks Wilt, If you want to look at crops you can work your way through my webpage menu structure and find them, but I do prefer plots for ease of comparision.

silvex wrote in post #9615632
Excellent graph Lester. SO the canon tcon is a better choice overall.

With the equipment I tested yes, but there could be sample variation, plus TCs may well work differently on zooms and primes, I would expect the difference to possibly be less with a zoom simply because primes tend to have better resolution.

Does anyone have any info on what tele-cons will work with the Tamron 28-75 2.8 and the Sigma 105 2.8 macro on the Canon 50D?
Clay

mayt444 wrote in post #9652933
Does anyone have any info on what tele-cons will work with the Tamron 28-75 2.8 and the Sigma 105 2.8 macro on the Canon 50D?
Clay

The Kenko would need to be used with both, as it has no protruding front element. Short FL lenses cannot accommodate the Canon 1.4x convertor.

Lester Wareham wrote in post #6119271
I just added to Kenko Pro 300 1.4X although I already have the two Canon converters, mostly for double stacking this and the Canon 1.4X on my 300mm f4L IS and general flexibility.

............... see full message at https://photography-on-the.net …p?p=6119271&pos​tcount=308

Anyone had success double stacking 1.4X TCs like this on the 7D?

It worked a treat with the 20D but the 7D AF seems to cope less well with this (AF point inconsistent) although I need to test more in better light and different subject ranges.

Lester Wareham wrote in post #9720999
Anyone had success double stacking 1.4X TCs like this on the 7D?

It worked a treat with the 20D but the 7D AF seems to cope less well with this (AF point inconsistent) although I need to test more in better light and different subject ranges.

I have double stacked a Canon 1.4x with a Kenko 1.4x. Two Canon 1.4x will not work to stack! The forward element protrudes by 7mm in front of the mount surface and the rear element is about even with the rear mount surface which protrudes 8mm, so there is >15mm of interference (add the thickness of the mount)

Lester Wareham wrote in post #9720999
Anyone had success double stacking 1.4X TCs like this on the 7D?

It worked a treat with the 20D but the 7D AF seems to cope less well with this (AF point inconsistent) although I need to test more in better light and different subject ranges.

Wilt wrote in post #9721104
I have double stacked a Canon 1.4x with a Kenko 1.4x. Two Canon 1.4x will not work to stack! The forward element protrudes by 7mm in front of the mount surface and the rear element is about even with the rear mount surface which protrudes 8mm, so there is >15mm of interference (add the thickness of the mount)

Thanks Wilt, but I was specifically asking about the AF accuracy on the other people's 7Ds, I know it works fine for the 20D, but the AF accuracy has been jumpy on the 7D.

Hello everyone. I'm a beginner with a Xsi/450D and recently got a 2x telephoto zoom lens trying to take some close-ups without getting close and it only works on the stock 18-55 lens but on my other one, 75-300 EF is very blurry/matte and cant auto focus with TF lens on. Is there a problem with it or do they just not go together at all? Please help! Thanks

I read through much of this thread, especially the beginning. I've done some Google searches but I'm still struggling with this answer.

My wife and I have an XTi with a few different budget lenses. One of those budget lenses is the Sigma 70-300mm F4-5.6 DG Macro. My wife lately is having fun taking pictures of birds around the property but this lens still isn't getting quite close enough. We sure can't afford a better lens and I thought maybe a teleconverter might be a good patch for now.

But is there a teleconverter made that will work with the camera and lens we have? I can't find my answer and thought surely someone here would know. Would love to surprise my wife with this on her birthday this April.

Thanks for any help you can offer!

A decent TC is going to cost a fair bit and adding it to your current lens is going to mean manual focus only for starters, IQ on cheaper glass also usually takes a hit so I suspect you would be dissapointed with the results. Better to save the cash towards a better lens. If the budget is tight consider the Sigma 120-400 or if you can stretch to it a Sigma 150-500, possibly secondhand.

Also consider a set of Kenko tubes. They have no glass, but act as a spacer between the camera and lens, to get the lens further away from the sensor, which has a magnifying affect. The down side is, they make the lens lose maximum focus, it won't focus out to infinity anymore, but will focus closer. However, using the various lengths of tubes, 12, 20 and 36mm in a set, you can use them out to about 30-35 feet or so, and best of all, retain auto focus. I have been using them around my yard for 4 years now and they are great. I'll never sell mine.

Hello All, I wanted to ask if anybody here knows whether teleconverter Kenko TELEPLUS PRO 300 AF 1.4X DG will work and autofocus with Canon 350D body and Canon EF 100mm f/2,8 Macro USM (non-IS) lens? I have noticed a message on this page - http://www.thkphoto.co​m …/pro300af2x1_4x​dgx-b.html - that DFX version does not work with Canon 350D so I want to ask about the older DG version. Is anyone using it with this body and lens combination?
Thank you.

mildante wrote in post #10029178
Hello All, I wanted to ask if anybody here knows whether teleconverter Kenko TELEPLUS PRO 300 AF 1.4X DG will work and autofocus with Canon 350D body and Canon EF 100mm f/2,8 Macro USM (non-IS) lens? I have noticed a message on this page - http://www.thkphoto.co​m …/pro300af2x1_4x​dgx-b.html - that DFX version does not work with Canon 350D so I want to ask about the older DG version. Is anyone using it with this body and lens combination?
Thank you.

I can verify that the Kenko DGX version won't work correctly on a Rebel XT. I've heard that the DG version will work, but haven't personally tried it.

OregonRebel - Thank you. I have found some pictures on Flickr that say they were taken with Canon Rebel XT (350D) and Kenko 1.4x PRO DG so I assume it will work and will probably order it.