Canon Teleconverters - general questions

[ceejtank]

Reviving this thread. I am interested in the telephoto converters by canon.. would like to pair it with my Canon EF 70-300mm f/4-5.6 IS USM Lens (http://www.amazon.com/gp/product/B0007Y794O/ref=wms_ohs_product). Anyone know if the autofocus works with either the Canon EF 2X II Extender Telephoto Accessory(Amazon.com: Canon EF 2X II Extender Telephoto Accessory: Camera & Photo) or the same with the 1.4 magnification model?

I understand I'd be losing about 2 fstops while using this and need certain conditions to properly use this and good crisp shots - however I am willing to work with that. My question is - will I lose autofocus or anything else? I've been debating getting one of these for a few months. Having trouble getting good answers. I trust the nerdiness of this forum more than random internet websites (in some instances).

Edit: I now remember - autofocus will not work with this lens.

Thanks for looking!

 

[Dao]

1st of all, I think it is better if you starts a new thread.


As for the TC, I could be wrong but I think the Canon TC will not work with your lens. I believe it only works with the Canon L lens. 3rd parties TC may work such as the one made by Kenko.

 

[TheBiles]

Reviving this thread. I am interested in the telephoto converters by canon.. would like to pair it with my Canon EF 70-300mm f/4-5.6 IS USM Lens (http://www.amazon.com/gp/product/B0007Y794O/ref=wms_ohs_product). Anyone know if the autofocus works with either the Canon EF 2X II Extender Telephoto Accessory(Amazon.com: Canon EF 2X II Extender Telephoto Accessory: Camera & Photo) or the same with the 1.4 magnification model?

I understand I'd be losing about 2 fstops while using this and need certain conditions to properly use this and good crisp shots - however I am willing to work with that. My question is - will I lose autofocus or anything else? I've been debating getting one of these for a few months. Having trouble getting good answers. I trust the nerdiness of this forum more than random internet websites (in some instances).

Edit: I now remember - autofocus will not work with this lens.

Thanks for looking!

Canon teleconverters only work with L primes equal to or greater than 135mm, the 70-200 zooms, and the 100-400L.

 

[GooniesNeverSayDie11]

There is quite a difference in quality. Granted some conditions/subjects minimize this more than others. However, I used to use the 70-200 f/2.8 with 2x extender and also have the 400mm f/5.6 and there is no comparison. Perhaps the MKII with the Extender MKIII would be better. In small prints it probably wouldn't be as noticeable though.

 

[TheBiles]

There is quite a difference in quality. Granted some conditions/subjects minimize this more than others. However, I used to use the 70-200 f/2.8 with 2x extender and also have the 400mm f/5.6 and there is no comparison. Perhaps the MKII with the Extender MKIII would be better. In small prints it probably wouldn't be as noticeable though.

The 70-200 2.8 IS II is awesome with the 2x extender III.

Sent from my Nexus 7

 

[Overread]

*thread split*
In future please start new threads when asking questions. Whilst we fully support the use of searching to find previous answers, its best to start a new thread on a topic when the original thread is many years old.



Further, as said, the Canon brand teleconverters will not work with the lens you have listed. This is because the teleconverters have a protruding front element and many lenses have a rear element which pushes back too far so that the teleconverter physically cannot mount to the lens. With Zooms you'll often find that the rear of the lens can move quite a bit between one end of the zoom range and the other, so if you do check you'll see that part move in many.
You might have luck with 3rd party teleconverters. The Sigma brand ones have a smaller protruding front element and the pro series Kenko have the smallest of any teleconverter. That said even with those types of teleconverter you might have trouble with your lens (70-300mm tend to have a pretty flush rear element).

In addition teleconverters magnify the image, thus any softness or quality issues get magnified with a teleconverter. On a 70-300mm lens you'll already see a dip in sharpness at the 300mm end over the 70mm (esp if you shoot both with the largest apertures/smallest f numbers). Adding a TC will increase that problem, a 1.4TC might be ok but any more and it will be too soft - 2*TC the only zoom I think worth putting that on is the new 70-200mm f2.8 IS L MII.
Also preserving sharpness can help if you stop down a stop from wide open - but a 1.4TC also takes away a stop of light - f5.6 becomes f8 and if you stop down from there you're getting a very small aperture and a lot of light loss - which means its even harder to get suitable shutter speeds.

 

[TheBiles]

You can see the protruding front element of the Canon 2x III here:

It's around half an inch long at least from the contacts.

Sent from my Galaxy S III

 

[ceejtank]

*thread split*
In future please start new threads when asking questions. Whilst we fully support the use of searching to find previous answers, its best to start a new thread on a topic when the original thread is many years old.



Further, as said, the Canon brand teleconverters will not work with the lens you have listed. This is because the teleconverters have a protruding front element and many lenses have a rear element which pushes back too far so that the teleconverter physically cannot mount to the lens. With Zooms you'll often find that the rear of the lens can move quite a bit between one end of the zoom range and the other, so if you do check you'll see that part move in many.
You might have luck with 3rd party teleconverters. The Sigma brand ones have a smaller protruding front element and the pro series Kenko have the smallest of any teleconverter. That said even with those types of teleconverter you might have trouble with your lens (70-300mm tend to have a pretty flush rear element).

In addition teleconverters magnify the image, thus any softness or quality issues get magnified with a teleconverter. On a 70-300mm lens you'll already see a dip in sharpness at the 300mm end over the 70mm (esp if you shoot both with the largest apertures/smallest f numbers). Adding a TC will increase that problem, a 1.4TC might be ok but any more and it will be too soft - 2*TC the only zoom I think worth putting that on is the new 70-200mm f2.8 IS L MII.
Also preserving sharpness can help if you stop down a stop from wide open - but a 1.4TC also takes away a stop of light - f5.6 becomes f8 and if you stop down from there you're getting a very small aperture and a lot of light loss - which means its even harder to get suitable shutter speeds.

Thanks for the in depth analysis. Most forums I use say use a search button, if you find the same topic - use that thread. In the future when I find the threads if they're old, I'll start a new one.

That being said.. looks like I'll be saving up for a bigger L series lens in general.