Compare sharpness and IQ

blackstar

blackstar

Senior Member
These two images are not mine, but there was a serious critical debate about the photo gear used to produce them. In order to not bring in your personal biased (or intentional) opinion, none of the details is revealed. Just compare the images and opine on their sharpness and IQ: one is better or both are equal or the same.
Z81_3797-Enhanced-NR.jpg

Z81_4385-Enhanced-NR.jpg
 
BF Hammer

BF Hammer

Senior Member
2nd is only sharper due to having the cardinal having a "flatter" profile in the focus plane. And I can see the exif data anyhow so I can see why it has an advantage for being sharp front to rear above and beyond that.
 
S

SPV

New member
The sharpness of the feather in the 2nd photo says it is sharper. but I'm not an expert to judge. Will agree with the senior member's comment.
 
blackstar

blackstar

Senior Member
SPV said:
The sharpness of the feather in the 2nd photo says it is sharper...
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I think you are right in the same way as BF indicated (and I observed). However, IMO, if the focus points are on the eye, they get the same (or at least) sharpness there.
 
Clovishound

Clovishound

Senior Member
I would agree that number 2 looks a little sharper. I would point out that number one is noticeably noisier, which introduces another variable to the mix, unless that was the point of the exercise. Also, these are small images. To adequately determine if an image is really sharp, I normally enlarger to a much greater degree than these are posted at.
 
blackstar

blackstar

Senior Member
Clovishound said:
I would agree that number 2 looks a little sharper. I would point out that number one is noticeably noisier, which introduces another variable to the mix, unless that was the point of the exercise. Also, these are small images. To adequately determine if an image is really sharp, I normally enlarger to a much greater degree than these are posted at.
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The two images were shot at different times (days). The settings were also different: iso and aperture. Thus noise factors may set in. But that isn't so considered in the debate. The presentation of these images was first aimed to show the new lens - z 180-600 - can be as good as or better than 200-500 compared @ 500FL (2nd image) in sharpness/IQ. Then the 1st image was brought up to see if the new lens is not or little suffered to losing sharpness @ 600FL compared to @500FL. IMO, the answers to both questions are yes and yes. And yet some photographers disagree. What's your opinion?
 
Clovishound

Clovishound

Senior Member
What's your opinion?
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In order to make a fair comparison, I would take at least 4 pictures of the same exact subject, preferably a static one, using a tripod to exclude any camera shake. Two, one at 500mm and maximum aperture and a second stopped down one or two stops. I would then take two more at 600mm, again, one at maximum and another the same 1 or 2 stops down. With different apertures and ISO settings, you don't know what differences are from resolution at a given focal length, and which are from changes in settings. It would also be helpful to do the same with the 200-500mm at 500mm, if available for the test, don't know how many folks would have both to try it.

I have no doubt that the new lens will outperform the 200-500, even at 600. While, an excellent lens for the money, the 200-500 barely makes the grade for 36MP, whereas the Z lens are reputed to be optimized for the newer high resolution sensors. It should be noted that not many FX lenses make the grade of 36MP resolution or higher. Link: Why Nikon Should Not Make DSLRs Over 36 MP
 
BF Hammer

BF Hammer

Senior Member
blackstar said:
The two images were shot at different times (days). The settings were also different: iso and aperture. Thus noise factors may set in. But that isn't so considered in the debate. The presentation of these images was first aimed to show the new lens - z 180-600 - can be as good as or better than 200-500 compared @ 500FL (2nd image) in sharpness/IQ. Then the 1st image was brought up to see if the new lens is not or little suffered to losing sharpness @ 600FL compared to @500FL. IMO, the answers to both questions are yes and yes. And yet some photographers disagree. What's your opinion?
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The 2 photos presented cannot be compared like that.

The question is really for a lab like imaging-resource.com to measure in a controlled setting. As presented here we have one image at f/8, 500mm and another shot at f/6.3, 600mm. For purely technical reasons, that puts the 600mm f/6.3 shot at a disadvantage because depth of field is going to be shorter. In addition the the 500mm f/8 subject is presenting as more flat to the focal plane so 100% of the cardinal is in the preferred depth of field range. The tail in the 600mm f/6.3 is outside of the ideal depth of field, even though the head is.

Put in plain English: If you are trying to make the lens look softer at 600mm on purpose, that is one way to do it.
 
blackstar

blackstar

Senior Member
Thank everyone for your input. Just remember this is another group's debate, not my project of comparison. I have no way of setting up a meaningful comparison for such a debate that I don't own either of the lenses (only anticipating my new 180-600). I agree with Clovis that from a technical view, the new z lens shall outperform 200-500. However, there is just someone who insists his/her images shot by 200-500 with z8,9 are all better in sharpness and IQ than all others' presented images shot by the new 180-600. There are images posted by this fellow to prove his/her point. And I saw no one could directly object, but only turn to other venues (e.g., online posting) of dismissing his/her proof. AW, the thing dragging on and the fellow is still waiting for his/her new 180-600... I hope until then this fellow will self-dismiss his/her point (so I can be more sure of keeping my yet shipping new lens).
 
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