Help with lens evaluation, please.

Joined
Jan 26, 2005
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Now that the rush of elation about getting my new lens is over, I've been looking critically at the
initial results, and decided to to do a little measurebating. I'd like to solicit some opinions on the results.

Comparisons are between the Nikon 60/2.8 micro, the Nikon 28-70/2.8, and Nikon 80-200/2.8. Shots were
taken on tripod, using the self timer to trigger the shutter. These are unresized crops". Processing was
limited to auto-levels.

The first image is each set is of the 60mm prime, followed by the 28-70mm/2.8 at 70mm, and the
80-200mm/2.8 at 80mm.

At full aperture

Subscribe to see EXIF info for this image (if available)

View attachment 6749
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At f/4

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At f/5.6

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At f/8

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It seems that the 28-70/2.8 doesn't get competitive until f/5.6. Is this normal, or is there a problem?
 
R

Removed User 2

Guest
IMHO I think your lens looks very fine.

The best test you can make is with a roll of slide film. Some lenses will behave differently on a D70 VS D100 VS D2H VS D2X... Besides, this is a 100% crop. F2.8 is very acceptable and of course, you are supposed to get better results from the micro lens, especially at a closer distance.

I know my 28 1.4 was totally crappy in my D100 and it shines on the D2H.
 
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Thanks for the input, NB. I'd try the lens with slide film, but I can't figure out how to cram in into my d70 :?.

In truth, I expected the 28-70 to give results equivalent to the 80-200 at f/2.8, so I became concerned
when I saw the comparitive results. Maybe I just need to reset my expectations, but the 28-70
doesn't seem significantly better that my recollection of images from the 24-120VR, and not as sharp
as the Tamron 28-75 at f/2.8.
 
Joined
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My thoughts

Frank,

The 2.8 certainly looks soft by comparison. I no longer own the 28-70 so can't offer much. I recall though that it was darn good wide open. Have you tried any real world shots wide open?

Tom
 
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Re: My thoughts

tweber said:
Have you tried any real world shots wide open?
Yes, but most of them were taken at very low shutter speeds, hand held, so I can't draw any conclusions
from them. I need to do a little more real world testing instead of shooting newspapers.
 
R

Removed User 2

Guest
What I see is that the 80-200 isn't much sharper at wide aperture... I also see the 28-70 lacks a bit of contrast at wide aperture, which isn't a bad thing either.

The usual USM will fix it easily.

The way I see things: for normal photographs that will get quickly printed, no PP is acceptable and the sharpness is fine.
Once you want to blow-up the keepers, then you'll play with black, gray and white point, play with curves and contrast and then add USM. All this will bring the quality where it's supposed to be.

Your 28-70 example reminds me of my 80-200mm 1 ring version wide open.

I understand you tested only at 70mm but what really is important on the 28-70 lens is the wide end. This is what makes this zoom special. If it's soft at 28, then you should return it. I believe the key to look after is on the wide end.
 
N

nfoto

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Hand-held shots for testing sharpness? You must be joking, right?
 
Joined
Mar 18, 2005
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I use the 17-55 & these 28-70 shots look soft to me. Here is a quick shot I just took of the Feb 2005 Issue of National Geographic cover. This was was shot handheld, at fairly slow speed (exif below). I'm sure I could do better with a tripod & shutter release, but its in my gf's car.

I just did levels & cropped for 100% to keep the test somewhat standard.

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I can get the tripod out around 4:00 today for a better test if you'd like, but this should give you an idea.

------------------------------------------------------------
File name: _D2H2605_2.jpg

Camera make: NIKON CORPORATION
Camera model: NIKON D2H
Date/Time: 2005:03:31 12:07:20
Flash used: No
Focal length: 55.0mm
Exposure time: 0.033 s (1/30)
Aperture: f/2.8
ISO equiv.: 200
Metering Mode: matrix
Exposure: aperture priority (semi-auto)

Hope this helps.

Dave
 
N

nfoto

Guest
My comments are refering to the fact that corners of the image (used on F5) are less sharp unless you stop down a couple of stops, to say f/5.6. this is due to field curvature and would be less important on a DSLR/DX-format.

Also note that most zoom lenses will have more field curvature when they are focused close. this propensity differs between lenses so it is unwise to compare lenses focused on near subjects.
 
Joined
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Another from inside the National Geographic. This time I used a tripod & remote. Just auto levels & 100% crop. Image data below.

Is this helping, or are we comparing apples to oranges?


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------------------------------------------------------------
File name: _D2H2607_2.jpg

Camera make: NIKON CORPORATION
Camera model: NIKON D2H
Date/Time: 2005:03:31 12:26:43
Flash used: No
Focal length: 55.0mm
Exposure time: 0.033 s (1/30)
Aperture: f/2.8
ISO equiv.: 200
Metering Mode: matrix
Exposure: aperture priority (semi-auto)

Dave
 
Joined
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STOP THE PRESSES!

I've been reviewing my methodology, and it sucked :oops:.

I took my unresized samples from the top of the page, not the middle. I re-did the test, using a center crop, and the results are entirely different (duh).

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View attachment 6761


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Conclusions:

I'm a weenie.
I"m gong to leave the lens testing to the pros.
The 28-70 looks just fine.

Thanks to all for helping me get over my panic attack.
 
Joined
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NB23 said:
I'm glad you're now feeling secure. To me it was obvious your lens was good...
It was just a mild panic attack, NB. Thanks for helping me work my way through it.

I think I'll use Chris's approach from here on out. I won't let testing get in the way of my subjective
pride of ownership :twisted:.
 
Joined
Jan 25, 2005
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Alabama
Hey Frank,


Unless you are Bill Gates or some other rich SOB, it is hard not to have buyers remorse, especially when you are spending hard cash on a hobby. Your panic is completely understandable. ;-)

Glad everything turned out OK. BTW, I agree with your assessment on one thing; leave the lens testing to Ron and Bjorn.... :lol:

Frank
 
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