What are your opinions about teleconverters...

[Neil S.]

I am looking for your general opinions about teleconverters, and what you feel are their strengths and weaknesses. I am aware of the reduction in max aperture that comes with them, as well as the reduction in sharpness (or so I hear).

Also, if anyone owns the Canon 2x extender III I would love to hear your opinions on it. The ability to make my 70-200mm 2.8 a 140-400mm (224-640mm with crop factor) is pretty appealing. I just wish it wasn’t so expensive, but I guess for what it does it isnt really that bad.

I own the Canon 1.4x extender II and its ok, but I wasnt really that impressed with the image quality from it. I think the mk III ones are better in this area based on what I have read though.

Neil

 

[Overread19]

Good teleconverters have very good optics in them and can give some great results; they are however highly dependant upon being mounted to a good quality lens as not all lenses can take a telconverter without problems. A 1.4TC MII or MIII have very similar image quality effects, the MIII is better overall but its not a night and day difference (esp on crop sensor) and its a similar story for the 2*TC but with slightly more gain with the MIII ( and again edge sharpness is the bigger area of improvement and not as evident on crop sensors).


As for your 70-200mm f2.8 IS L MII it takes a teleconverter up to a 2*TC (MII or MIII) exceptionally well and will perform to a standard similar to the 100-400mm at the 400mm mark; with both showing a noticeable improvement when stopped down to around f7.1/f8 (wide open is usable certainly, but you get a good jump when you stop a little ways down). If you search around you should be able to find many good comparative reviews on this combo (careful not to read ones on the original 70-200mm f2.8 IS as that wasn't anywhere near as good as the MII with a 2*TC).

Myself I've used both of the 70-200mm f2.8 IS L lenses and whilst hte original got the 2*TC used about 4 times and the 1.4 almost never left it - the MII is more than capable of taking the MII and I'm quite happy to use it all the time when needed. Some examples with 100% crops:
Minsmere - a set on Flickr
70-200mm f2.8 IS L M2 test - a set on Flickr

 

[Neil S.]

Thanks Overread,

Ya I understand what you are saying about the quality of the attached lens being a factor. It’s a good thing for me that the 70-200 2.8 II is such a good performer, and it seems to be able to take TCs well from what you and others have said.

I just now went to www.the-digital-picture.com and was looking at test shots of lenses with TCs on them, and it was a pretty noticeable image quality difference. What’s more is that like you said you have to stop down to like f8 with the 2x to get the best possible quality. As I’m sure you are aware the 70-200 2.8 II is an awesome performer even wide open, so this part of it kind of sucks to be honest lol.

I guess when you compare the price of that lens and a TC to the price of a 400mm 2.8 its actually pretty good performance. Also this way I have a lens that performs outstanding at 70-200 and then fairly descent from 140-400.

 

[Overread19]

Remember with the 2*TC the 70-200mm is already f5.6 when wide open so f8 is only slipping down one stop - its sadly a factor for any of the superzoom type lens arrangements that they work their best (both sharpness and reduced aberrations) when stopped down. However its interesting to note that I know several bird photographers who will shoot even wider lenses at f8 when the light allows to get suitable depth of field at range for birds - so its not too big a limitation as it can first appear. Support it further if you need, with a speedlite and Better Beamer/Flash Extendor for pushing a bit of flash out at the 400mm and you've a solid setup

 

[bazooka]

Correct me if I'm wrong, as I don't own a TC yet but am in the same boat as the OP, but the TC doesn't affect aperture at all... it only affects the amount of light reaching the sensor. You can still use the lens at 2.8... but with a 2*TC you only get 5.6 worth of light. Just like using a ND filter, Right?

 

[Mike_E]

1.4 is good, 1.7 is OK, and anything above that you need to be desperate.

 

[kylehess10]

I recently purchased my first TC and I personally love them. You always have to do your homework though and know which one is right for you.

I have a Nikkor 300mm f/2.8 and from going through different reviews for a few days, I was able to narrow it down to the TC-17E II (1.7), since the 2x seemed to downgrade quality too much and a 1.4 didn't seem like enough extra focal length, but I personally love it. The TC has helped me get crystal clear shots from 400+ feet away. Definitely worth it


Here's a couple examples:


I took this pic with my 300 & 1.7x TC from above the Atlanta Braves dugout, and this pic is in the left field seats, about 400 feet away:

And I took this next pic even farther...up at a restaurant in the upper level in left field:

Here's to show where I was sitting:

 

[gsgary]

Take a look at the Kenko 2x 300 pro very sharp (600mm)

 

[kylehess10]

Here's another example with some of my unedited files


Here's one of my photos taken with the 300mm f/2.8 WITHOUT a TC:

FULL-RESOLUTION CROP:

Here's the same lens taken in the same spot but with the TC-17E II

FULL-RESOLUTION CROP:

 

[Neil S.]

Correct me if I'm wrong, as I don't own a TC yet but am in the same boat as the OP, but the TC doesn't affect aperture at all... it only affects the amount of light reaching the sensor. You can still use the lens at 2.8... but with a 2*TC you only get 5.6 worth of light. Just like using a ND filter, Right?

Ya I believe you are right about this.

I think the aperture of the lens is still the same, but its the TC that "reduces it" as you said. So I guess the max aperture of the lens is unchanged, but it is effectively reduced do to some factor involving the TC.

The additional distance that it places the lens from the sensor perhaps?

Neil

 

[Neil S.]

Take a look at the Kenko 2x 300 pro very sharp (600mm)

Gary,

I remember this photo from before, and was actually thinking a lot about it before you posted it (was looking though the other thread it was in rescently). The reason is because it is one of the most outstanding I have seen from a lens+TC combo.

That 300 of yours must be a really kick ass lens. I want a big telephoto so much, but I dont have the money.

I would be willing to take yours if you wanted to give it to me.:hug::

Neil

 

[Neil S.]

Remember with the 2*TC the 70-200mm is already f5.6 when wide open so f8 is only slipping down one stop - its sadly a factor for any of the superzoom type lens arrangements that they work their best (both sharpness and reduced aberrations) when stopped down. However its interesting to note that I know several bird photographers who will shoot even wider lenses at f8 when the light allows to get suitable depth of field at range for birds - so its not too big a limitation as it can first appear. Support it further if you need, with a speedlite and Better Beamer/Flash Extendor for pushing a bit of flash out at the 400mm and you've a solid setup

I wanted to thank everyone who posted here so far, and I appreciate the input.

Overread: Ya I guess you are right that having to stop down to f/8 isn’t really that big of a deal. The only thing that could be a problem is either significant low light, or if you are really trying for a shallow DOF.

The weight and cost savings from being able to carry one lens (70-200) and then transform it to a 140-400 is a pretty awesome capability. I think I should get a 2x converter, and probably the III just because I like getting the most recent version.

Thanks again for all your advice mate.

Neil

 

[gsgary]

Take a look at the Kenko 2x 300 pro very sharp (600mm)

Gary,

I remember this photo from before, and was actually thinking a lot about it before you posted it (was looking though the other thread it was in rescently). The reason is because it is one of the most outstanding I have seen from a lens+TC combo.

That 300 of yours must be a really kick ass lens. I want a big telephoto so much, but I dont have the money.

I would be willing to take yours if you wanted to give it to me.:hug::

Neil

It's a 300F2.8L non is
This shot is with the Kenko 2x and Canon 1.4x fitted to 300mm and it will still auto focus, got stuck on the far side of the track because i missed the crossing time