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Old Feb 4, 2007, 1:03 AM   #21
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So, I did some comps of the different lenses, and really there are no dramatic differences at all.

Here is the Minolta 50 1.4 at it's widest aperture. all images are 100% crops.The focus is at the "E" in "STONE MILL" in each shot.




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Old Feb 4, 2007, 1:07 AM   #22
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Minolta 50 1.4 @ 1.7
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Old Feb 4, 2007, 1:09 AM   #23
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Minolta 50 1.7 @ 1.7
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Old Feb 4, 2007, 1:13 AM   #24
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And now here are four lenses at 50mm f4.5, starting with the Minolta 50 1.4




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Old Feb 4, 2007, 1:15 AM   #25
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Minolta 50 1.7 @ f4.5
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Old Feb 4, 2007, 1:18 AM   #26
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KM 28-75 f2.8 @ 50mm f4.5


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Old Feb 4, 2007, 1:21 AM   #27
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and the Tamron 28-300 XR @ 50mm f4.5


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Old Feb 4, 2007, 1:28 AM   #28
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My previous assumption that the fixed lenses blow away my zoom lenses was erroneous and apparentlybased on focus errors. All of these lenses are very comparable in sharpness, detail and color, with both of the fixed lenses maintaining a slight edge. At the same timeI found that the 50 mm lenses are still very crisp (at least at their center of focus) even at their widest aperture. This despite some reviews I have seen stating that f1.4 and f1.7 were supposedly"unusable".

I decided to sell the 50mm f1.4, simply because 1/2 an f-stop to me is not worth letting go the extra $150 I can fetch for it on ebay.

What do you guys think? By the way, here is the resized full image of the beer bottle taken with the Minolta 50 f1.4 @ F1.7. I did not bother posting the comparisons because they would be indistinguishable at this size. I am only posting this so you get an idea of the crop area ratio.




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Old Feb 4, 2007, 6:05 AM   #29
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Very good choice for a test image.

In examining the photos, I was paying particular attention to the top stroke of the lowercase "e" in the word "bouquet" near the bottom of the frame.

In the first frame (Minolta 50 1.4 @ 1.4) the stroke is gone.

In the second (Minolta 50 1.4 @ 1.7) the stroke is better defined than in the third (Minolta 50 1.7 @ 1.7)

In the fourth (Minolta 50 1.4 @ f4.5) and fifth (Minolta 50 1.7 @ f4.5), the strokes look about equal but both look sharper than the sixth (KM 28-75 f2.8 @ 50mm f4.5.)

The seventh (Tamron 28-300 XR @ 50mm f4.5) looks amazingly sharp, but the image of the bottle is larger. I presume that you kept the bottle and the camera in the same position and just changed lenses. That would have been fine for the other lenses, but the Tamron 28-300 XR is longer, so the distance between the bottle and the objective lens would have been less, so the photo is from a closer vantage point.

Anyway, that's my opinion, and thanks for all the effort. This was, no doubt,a useful exercise for all of us.
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Old Feb 4, 2007, 12:42 PM   #30
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TCav wrote:
Quote:
Very good choice for a test image.

In examining the photos, I was paying particular attention to the top stroke of the lowercase "e" in the word "bouquet" near the bottom of the frame.

In the first frame (Minolta 50 1.4 @ 1.4) the stroke is gone.

In the second (Minolta 50 1.4 @ 1.7) the stroke is better defined than in the third (Minolta 50 1.7 @ 1.7)

In the fourth (Minolta 50 1.4 @ f4.5) and fifth (Minolta 50 1.7 @ f4.5), the strokes look about equal but both look sharper than the sixth (KM 28-75 f2.8 @ 50mm f4.5.)

The seventh (Tamron 28-300 XR @ 50mm f4.5) looks amazingly sharp, but the image of the bottle is larger. I presume that you kept the bottle and the camera in the same position and just changed lenses. That would have been fine for the other lenses, but the Tamron 28-300 XR is longer, so the distance between the bottle and the objective lens would have been less, so the photo is from a closer vantage point.

Anyway, that's my opinion, and thanks for all the effort. This was, no doubt,a useful exercise for all of us.

Thanks for your feedback. However, I don't think that using the "e" in bouquet is a fair comparison since it was not my point of focus, and honestly the angle at which I held the camera probably changed a little from image to image, meaning that in some images the whole bottle could have been on one plane, while in another I faced it somewhat angled.The best area to compare is around the "E" in "STONE MILLS". If I get a chance today I'll do something using a tripod to have a truly controlled test environment.

As far as the Tamron is concerned with its internal focus system it often does not correspond to the same focal length as other lenses, especially fixed lenses. Although it might read 50mm it could be somewhat off. Regardless, everytime I run these tests I am amazed by the Tamron's quality. It can certainly at least hold its own compared to any premium lens I tested. Some snobs might scoff at it, but I rather trust what I see for myself.

I am about to list the Minolta 50 f1.4 for $250 on ebay. If I can command that price for it, I rather take the money and run than having an extra 1/2 f-stop which I probably will use at most once a year.

Rainer

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