Test shots stacking the 1.4 and 2x extenders (Page 2): Unfortunately, this is not an example that demonstrates anything beyond goodish. Lots of purple fringing. The loss of fine detail...

CHG_CANON Loc: the Windy City

bull drink water wrote:

the point is that quality lens/extender combos can deliver good to great images. check you tube if you doubt.

Unfortunately, this is not an example that demonstrates anything beyond goodish. Lots of purple fringing. The loss of fine detail is the next drawback. On a full frame 200mm x 2 x 1.4 gives you 560mm. There's plenty of lenses that cover that focal length without resorting to extender x extender and provide much better image quality. Both the 1.4 III and 2.0 III extenders run about $425 so that's $850 that could be applied to more effective approaches. Along with the appropriate lenses and technique, both extenders produce excellent (aka great) results when only one is used. Combined, maybe worth an investigation, but only if the purpose was to show the limitations of the combination.

thelazya Loc: Wendell, MN

What? Where is everyone saying how these cause so much loss of light that you won't be able to do it??

Wmetcalf Loc: Rogersville, Mo

thelazya wrote:

What? Where is everyone saying how these cause so much loss of light that you won't be able to do it??

Sure you can do it, just can’t autofocus.

jackpinoh Loc: Kettering, OH 45419

thelazya wrote:

What? Where is everyone saying how these cause so much loss of light that you won't be able to do it??

Teleconverters cause both a loss of image quality (because of the extra optical elements and the buildup of optical element position errors) and a reduction of light that reaches the focus sensor (because that light comes from a much narrower field of view than the lens field of view without the teleconverter). For a f2.8 lens, the 1.4TC costs one stop (f2.8-->f4) and the 2.0TC costs two stops (f4-->f8). At f8, most DSLRs have between 0 and 15 AF points available. This greatly reduces their AF capability. It makes handheld AF difficult or impossible, and some DSLRs will not AF at all unless on a tripod with good light on the subject.

jim quist Loc: Missouri

jackpinoh wrote:

Teleconverters cause both a loss of image quality ... (show quote)

I only use one focus point and hand held auto focus was not difficult or impossible.

jim quist Loc: Missouri

Wmetcalf wrote:

Sure you can do it, just can’t autofocus.

The auto focus works fine.

imagemeister Loc: mid east Florida

jim quist wrote:

Test shots with a Canon 1dmk4 stacking the 1.4 & 2x extenders with 70-200 2.8 lens.

Sooo, you are at 560mm at f8 on a 1.3X crop sensor and the camera was released in '09 and has no trouble with auto focus? And, you have no trouble handholding and getting SHARP pictures ?? Hmmm

Not saying it is impossible - just HIGHLY unlikely- at least for my normal image quality standards.

..

mwsilvers Loc: Central New Jersey

jim quist wrote:

Here's high Resolutions for you

It was an interesting exercise. And although far from pin sharp, the images are a lot sharper than I would have expected with stacked extenders, and of course the chromatic aberration on the mallard's neck is extreme. But, both images are still quite usable depending on what you use them for.

jim quist Loc: Missouri

imagemeister wrote:

Sooo, you are at 560mm at f8 on a 1.3X crop sensor and the camera was released in '09 and has no trouble with auto focus? And, you have no trouble handholding and getting SHARP pictures ?? Hmmm

Not saying it is impossible - just HIGHLY unlikely- at least for my normal image quality standards.

..

I heard a speaker say: "Those who say it cannot be done should stay out of the way of those who are doing it."

PhotoKurtz Loc: Carterville, IL

That's a great idea! Why didn't I think of that??? Will post a couple of my own on a separate thread.

Notorious T.O.D. Loc: Harrisburg, North Carolina

If I can beg, borrow or maybe rent a 1.4 Extender III I will try this on my 1Dx MkII. It would be an interesting experiment... I will have to see if I have some shots with my daughters T3i and the 2x with my 70-200.

imagemeister Loc: mid east Florida

CHG_CANON wrote:

Unfortunately, this is not an example that demonst... (show quote)

I would MUCH RATHER optimize the native len's IQ, save several stops of ISO/get faster more accurate FOCUS/AF and CROP and use AI pixel enlargement software.
.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

bull drink water wrote:

the point is that quality lens/extender combos can deliver good to great images. check you tube if you doubt.

If you don't mind a bit of softness and lots of CA - at least in these sample images. I agree that image quality can be excellent - but generally with prime telephoto lenses, and of course the 180-400 Nikkor or the 200-400 Canon zooms, which have dedicated TCs. One should not expect more than average results with lesser lenses.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

imagemeister wrote:

Sooo, you are at 560mm at f8 on a 1.3X crop sensor and the camera was released in '09 and has no trouble with auto focus? And, you have no trouble handholding and getting SHARP pictures ?? Hmmm

Not saying it is impossible - just HIGHLY unlikely- at least for my normal image quality standards.

..

amfoto1 Loc: San Jose, Calif. USA

jim quist wrote:

The auto focus works fine.

However, you're using a 1D-series camera, which have had f/8 focus capability for a long time.

That's not the case with many other Canon DSLRs. A lot of them have been f/5.6 limited, so would not be able to autofocus an f/2.8 lens + 1.4X + 2X.

Also, you're using the two TCs stacked behind an f/2.8 lens. In addition to one of those, in another thread the poster was asking about using the two TCs behind a 100-400mm, which is an f/4.5-5.6 lens. With the two TCs on it, the combo become and f/13-16 combo that won't be able to autofocus on any Canon DSLR.

I was surprised to see the amount of chromatic aberration (purple fringing) in your Canada goose image. I didn't see any of that when I used the same TCs stacked behind my 500mm. Is that the first version EF 70-200mm f/2.8 IS USM or the non-IS version? The reason I ask is because those are the only two Canon 70-200s that don't use fluorite, which can be quite effective reducing CA.