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05-24-2008, 04:27 AM   #1
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What do you think of this 16-50 copy

Let me know if this is a keeper or not.

It definitely has some decentering issues. Do those of you with a good copy have ZERO decentering issues???

Both photos are at 2.8

The crops of the newspaper are a crop from the left center and right side respectively. You can see the left and center crops are sharp but the right side is soft. This is at 50mm

The other photo is a shot i took of myself to get a semi "real world" result. Looks sharp. This was at 16mm and 2.8 with a shoot through brolly. also included is a 100% crop in the image

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05-24-2008, 04:38 AM   #2
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Here are some crops at 16mm 2.8

Pardon my spray painting but my text tool is not working in photoshop...

Crops are C for center R for right and L for left
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05-24-2008, 05:49 AM   #3
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Even considering wide open at max angle is going to be soft on the sides, to me, right side definitely looks softer than left, though it's hard to tell just by how much using these small crop sizes.

The "real" photo looks great, though and your eye crop is very nice.

Perhaps try a more "real" test? Take a picture of a street, etc. with a roadsign or other detailed object in the right of the frame and see if the fuzziness is bearable or even detectable.

Personally, if I had just spent that amount of money on a lens, I would make sure it's damn near perfect, but that's me. THen again, I rarely do any image cropping off-center, so I would probably test this lens more to see how it holds up.
05-24-2008, 06:23 AM   #4
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Yeah, but it still looks pretty good... Remember that if you're going to do a test like that, you have to make absolutely certain that the newsprint is exactly parallel to the plane of the sensor - and the same distance - even a little 'tilt' can make one side just slightly off. It looks like you're holding the camera, or was it tripod mounted? If you were holding it, you'd have to get lucky to have everything parallel.

A better test might be to set yourself up between two real-world objects, like statuettes or something with 3-d to them, then take the shot and look at focus.

Remember that you won't be taking pictures of print with this lens ever again after these tests, so ultimately it doesn't matter what newsprint looks like at 100% crop.

Based on your image of you, I'd says it's a very good copy. My first copy was much worse than that.

.

05-24-2008, 06:36 AM   #5
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the test was done on a tripod. The tripod/camera was perpendicular to the wall where I made sure to tape the newspaper flat. I have been able to repeat the right side softness with other photos of flat things as well.
05-26-2008, 03:15 AM   #6
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Anyone else with a 16-50 care to comment on the quality of my copy??? Its going back on tuesday unless someone says I shouldn't expect anything better from this lens.
05-26-2008, 03:31 AM   #7
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To be perfectly honest. Even if that 100% crop is a bit soft, will you _ever_ notice it in a normal photo? If your going to go microscopic on every piece of equipement you ever buy, you will never be statisfied with anything.

imho, go out and take a few hundred shots with it, as normal usage, not as test pictures. Then sit down and look thru them, I promise there will not be a single photo that you will be "OH NO THATS A BAD PICTAR!! AND ITS ALL THE LENS FAULT!". Have fun with your camera instead, take pictures, don't get snowed in on details like that.
05-26-2008, 04:12 AM   #8
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The large picture looks fine. The R, L, C samples that you posted will almost never get it edge to edge sharpness from that lens. Check for Front Focus/Back Focus issues. Take some 'real world' shots and compare it to your 'kit' lens in the same situations and see how it compares.

05-26-2008, 05:07 AM   #9
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QuoteOriginally posted by Zewrak Quote
... take pictures, don't get snowed in on details like that.
I always want to get what I pay for ...
And I have a really bad side of my self ... when there is the slightest defect I know off, my eye gets there all the time and I see it (even if it isn't realy there )
05-26-2008, 05:39 AM   #10
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I guess what I am trying to determine is if another copy will have less "decentering" issues. I defiantly notice the right side softness, particularly at 50mm and f2.8. You can see it pretty well in my first post.

This being said, the lens is quite sharp in the center at all Fstops. I took the lens out yesterday with some friends of mine for a little photo shoot. None of these are at 2.8 (most are at f6-9).

So I guess my question is, does anyone out there with a "good" 16-50 have no noticeable decentering issues?
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05-26-2008, 05:46 AM   #11
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QuoteOriginally posted by gkopeliadis Quote
I always want to get what I pay for ...
And I have a really bad side of my self ... when there is the slightest defect I know off, my eye gets there all the time and I see it (even if it isn't realy there )
If you buy a car, do you dissassemble the engine to check for internal scratches? After all, they might affect how the car performes, you might loose some engine effect.

If you buy a watch do you take it apart or even measure it against the atomic clocks?

If you buy a meter of cloth, do you measure it down to micrometers?

If you buy an electric gadget, do you measure so that it does use exactly as many watts as it is labeled to do? Or that the moving parts move exactly as much as they are supposed to?

If you do, you own nothing. Because you will never be statisfied. Somehow though, people with digital cameras have some urge to notice nonexistant problems. There are literally billions of pictures in the world, and I dare to say 99.9% of them are shot with equipement that has flaws. We are not using multibillions of dollars worth of spacecraft items. We are using consumer level cameras, every part in the camera will be at risk of a flaw and I am sure that every digital camera that is sold on a consumer base, is flawed, if you look close enough.

When we start worrying that much for the equipement, no pictures will be taken, instead of taking shots of stuff outside our house, we will be inside fiddling with charts, newspapers and other laboratorytests, that have no impact on reallife photography. Everyone seem to think they need top notch, on an atmoic level perfect equipment and that it will make you take professional looking pictures.

While the truth is, as long as the stuff works within the expected tolerance of errors, professional photographers use their equipment on real subjects. They don't waste time counting pixels. If they did, noone of us would have heard of them, because every piece have faults, quirks that makes it unique, but not bad.

It's one thing if it miss focus all the time, have scratches etc. But then there would not have been a thread here, then it would have been sent in for a new one. But the lense in this discussion is good. Send it in and you'll get a new one that has some other quirk, and send that in, get a new one with another quirk... etc.

If you want a perfect lense, then pay up and have one made personally for you, where the factory guarantee its exactness and quality. ANd then pay up the several 10.000'ds of dollars it will cost to have it made.
05-26-2008, 05:54 AM   #12
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QuoteOriginally posted by qksilver Quote
I guess what I am trying to determine is if another copy will have less "decentering" issues. I defiantly notice the right side softness, particularly at 50mm and f2.8. You can see it pretty well in my first post.

This being said, the lens is quite sharp in the center at all Fstops. I took the lens out yesterday with some friends of mine for a little photo shoot. None of these are at 2.8 (most are at f6-9).

So I guess my question is, does anyone out there with a "good" 16-50 have no noticeable decentering issues?
I'd say thats some good pictures, if they would have been better with another lense, I don't know. But I'd say thats pictures I'd be happy about. No matter what lense I had used.
05-26-2008, 06:04 AM   #13
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QuoteOriginally posted by Zewrak Quote
If you buy a car, do you dissassemble the engine to check for internal scratches? After all, they might affect how the car performes, you might loose some engine effect.

If you buy a watch do you take it apart or even measure it against the atomic clocks?

If you buy a meter of cloth, do you measure it down to micrometers?

If you buy an electric gadget, do you measure so that it does use exactly as many watts as it is labeled to do? Or that the moving parts move exactly as much as they are supposed to?

If you do, you own nothing. Because you will never be statisfied. Somehow though, people with digital cameras have some urge to notice nonexistant problems. There are literally billions of pictures in the world, and I dare to say 99.9% of them are shot with equipement that has flaws. We are not using multibillions of dollars worth of spacecraft items. We are using consumer level cameras, every part in the camera will be at risk of a flaw and I am sure that every digital camera that is sold on a consumer base, is flawed, if you look close enough.

When we start worrying that much for the equipement, no pictures will be taken, instead of taking shots of stuff outside our house, we will be inside fiddling with charts, newspapers and other laboratorytests, that have no impact on reallife photography. Everyone seem to think they need top notch, on an atmoic level perfect equipment and that it will make you take professional looking pictures.

While the truth is, as long as the stuff works within the expected tolerance of errors, professional photographers use their equipment on real subjects. They don't waste time counting pixels. If they did, noone of us would have heard of them, because every piece have faults, quirks that makes it unique, but not bad.

It's one thing if it miss focus all the time, have scratches etc. But then there would not have been a thread here, then it would have been sent in for a new one. But the lense in this discussion is good. Send it in and you'll get a new one that has some other quirk, and send that in, get a new one with another quirk... etc.

If you want a perfect lense, then pay up and have one made personally for you, where the factory guarantee its exactness and quality. ANd then pay up the several 10.000'ds of dollars it will cost to have it made.

Wow!!! I unconditionally surrender
05-26-2008, 08:46 AM   #14
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1) QkSilver, your friends are incredibly attractive. Wow. The pictures also turned out very nicely and I really like how #2 turned out. Great lighting, nice pose, and the background is actually incredible -- I would have guessed it to be a studio shot!


2) I had to chime in on this:

QuoteQuote:
If you buy a watch do you take it apart or even measure it against the atomic clocks?
Truth be told, I bought a watch that synchronizes with the U.S. Atomic clock in Colorado every morning...does that count?
Yes, it's a curse This is probably why I'm currently computing every lens permutation known to man in trying to decide what I will spend my near-future cash on ...*sigh*
05-26-2008, 09:10 AM   #15
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both your technical and practical photos look quite good. Odds are that a second copy would probably be no better.

For pixel-peeping, the worst case is seeing bad smearing which doesn't really show in your photos.
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