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Author Topic: The Extender Question  (Read 11231 times)

John Sheehy

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The Extender Question
« Reply #20 on: June 13, 2006, 08:47:32 am »

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i have the 100-400 and 300 4.0 which with 1.4x is just noticebly better than the 1-4 at 400.  i would suspect that the 400 5.6 is just noticebly better than the 300 4.0 +1.4.[a href=\"index.php?act=findpost&pid=67592\"][{POST_SNAPBACK}][/a]

My 300 f/4L IS is not as sharp as my 100-400 at 400, wide open.  The 300 needs to be stopped down a bit, at which point it is a little sharper than the zoom.  The 300 with a 1.4x underperforms the zoom at 400 in every way.  I get more subject detail with the zoom with a 1.4x, and 2x.  with them stacked, very little extra subject detail is captured.  I intend to get another Kenko 1.4x, because I like to keep one on the camera for birds, and stacking to 2.8x is usually a waste, or impractical because of lighting.  Two 1.4xes would be better, in terms of returns.  I only like to use the 2.8x stack when the subject is in direct sunlight.  The extra magnification in the viewfinder makes manual focusing more precise.  In the dark, it makes it worse.

With the 2.8x stack, I get a lot of misses due to tremors, misfocus due to rocking or subject movement, but when I get a hit, I get a lot more subject detail than I would without the TCs, or with just a 1.4x.

I believe that people are too quick to judge TC usefulness based on the 100% pixel view, which I think is really kind of irrelevant.  For the type of photography one is doing when they need more reach and use a TC, the subject is what matters, and 2x more detail in 4x as many pixels is a gain, even if the pixels themselves lose contrast.  Cropping is not a viable option IMO, with the level of artifacts present, when light is low.  Many people say that an upsampled crop is better than using a TC, and that may be true for certain lenses, and may be true with AF, but it is not true in my experience.  My most detailed bird shots are almost always the ones taken with the TCs.

It takes a lot of skill to use TCs properly, and judge when to use them or not, especially when combined with slow lenses.  They are not "plug and play".
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Gregory

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The Extender Question
« Reply #21 on: June 14, 2006, 12:50:12 pm »

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My 300 f/4L IS is not as sharp as my 100-400 at 400, wide open.  The 300 needs to be stopped down a bit, at which point it is a little sharper than the zoom.  The 300 with a 1.4x underperforms the zoom at 400 in every way.
[a href=\"index.php?act=findpost&pid=68078\"][{POST_SNAPBACK}][/a]

thank you. that was helpful.

I do a lot of bird photography. I'm still learning and have a long way to go.

I'm currently using a 70-200/2.8L with a 2x and while it's ok, it's frequently not 'close enough' (and objects out of focus sometimes get doubled). for that reason, I'm considering a 300 or the 100-400. I figured that a 300 + 1.4x would give me a better picture than the 100-400 (both choices end up with f5.6) but you've discovered otherwise. you may have saved me money ;-)

and I'd never have considered stacking two 1.4x's. you only lose 2 stops and get 2.8x extension. it's a shame that I already have the 2x although they cost the same which complicates things a little.

I guess my options are to get the 100-400 (would I need a 1.4x if I already have the 2x?) or save a while and get the 300/2.8L.

incidentally, have you benefitted from IS when photographing birds without a tripod?

Gregory
« Last Edit: June 14, 2006, 12:50:51 pm by Gregory »
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allan67

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The Extender Question
« Reply #22 on: June 14, 2006, 04:28:21 pm »

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and I'd never have considered stacking two 1.4x's. you only lose 2 stops and get 2.8x extension. it's a shame that I already have the 2x although they cost the same which complicates things a little.
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Hello,

I don't think you'll get 2.8x with two 1.4x extenders. You'll get 1.96x (1.4*1.4).
You can get 2.8 with one 1.4 and one 2 (1.4*2).

Allan
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Gregory

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The Extender Question
« Reply #23 on: June 14, 2006, 10:05:43 pm »

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I don't think you'll get 2.8x with two 1.4x extenders. You'll get 1.96x (1.4*1.4).
You can get 2.8 with one 1.4 and one 2 (1.4*2).
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whoops! silly me. thank you for the correction.

Gregory
« Last Edit: June 14, 2006, 10:06:40 pm by Gregory »
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John Sheehy

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The Extender Question
« Reply #24 on: June 15, 2006, 08:11:34 am »

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and I'd never have considered stacking two 1.4x's. you only lose 2 stops and get 2.8x extension.

Two 1.4xes make 2x, not 2.8x.  The reason I want a second 1.4x is that I like to leave the 1.4x on the the camera, and when I want 2x, I'd have to take the 1.4x off and expose the chamber to dust, or add the 2x for 2.8x, which gains very little subject detail for the amount of light it loses.  The Newest Kenko 1.4x converters seem to be great, too, and don't seem to lose any noticeable contrast.  I can't tell the difference with or without mine without looking at the EXIF, on a well-focused image.  With my 2x Tamron SP, I can see in the review image that there is a slight loss of contrast.  There is actually more contrast with the Kenko 1.4x between the camera and the Tamron 2x than the Tamron by itself, it seems.

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incidentally, have you benefitted from IS when photographing birds without a tripod?[a href=\"index.php?act=findpost&pid=68179\"][{POST_SNAPBACK}][/a]

IS is not a gimmick; it lets you hold the camera in lighting that would be otherwise impossible.  It does nothing for subject motion, though.

For critical sharpness, it is good for about 1.5 stops.  For a 4x6 print, it is good for quite a bit more.
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stever

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The Extender Question
« Reply #25 on: June 15, 2006, 09:17:43 pm »

i really believe that if you get better results from the 100-400 than the 300 +1.4x you should send the 300 in to Canon for calibration (perhaps you have an extraoridinary 100-400, but that would be surprising) -- i find both combinations benefit greatly from stopping down to f8, and at least in some cases i get better results at 1600 and f8 than 800 wide open (subject and lighting related)

i've had zero issues with moderate resizing in photoshop after RAW processing - for birds and animals - no real experience with hard edge subjects

pleased to hear of good results with the kenko as i'd like an extender to use with the 100 macro without the 12.5 extension

okay, i'll retry the 300 with 2x even though every comparison i've done indicates it's not worth the trouble
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