05-15-2011, 04:58 PM
[quote name='hotbird' timestamp='1305474937' post='8333']
First of all I think that the reviews of PZ are an excelent and precise evaluation of lenses and I trust and use it all the time to make decisions to buy or not to buy a lens. So thanks for your great work so far.
But some of the coments and conclusions about the optical quality of the Nikon 80-400 in relation to the Canon 100-400 are in my view contradicting to your own MTF data for these two lenses. Comparing this data directly the Nikon shows a better MTF performace from the wide end to about 200mm and the Canon improves from than on to the far end at 400mm. In my view both lenses have their strong areas and their weeaknesses. Even if a comparison does not make real sense, because the lenses can not be used on the competitors bodies, I think 3,5 stars for the Canon versus 2 stars for the Nikon in "Optical Quality" seem not to represent your own MTF values and may not represent the true picture.
Strong and weak areas are about equal on both leses so in my opinion the number of stars for this category should be more or less the same. I can not judge on the Canon lens by experience, but I own and use the Nikon since many years. Generally I totally agree on what the data shows. The lens is quite a good perfomer between 80mm and 200mm and still okay at 300mm. At 400 mm it is definately lacking resolution and contrast. Looking at the MTF data the Sigma is no winner in any area and for that reason not an option for any of the two at all, but it did recieve more stars in the "Optical Quality" section, which I find a bit mislading to readers. Not that I have seen any test in the past were the Sigma outperformed either, the Canon or the Nikon. Also the "Price/Performance" section with 2 stars for Nikon ( around 1500 €) and 4 stars for Canon (around 1400 €} seems not to represent reality as for a very similar price there is a very similar perormace of both lenses with a lack in eiter end of the zoom range, according to your own MTF dataset.
For the ones who always point at the Nikon 200-400 they would get instead and which is clearly the performance winner. There are many jobs were weight and size matters so much more than resolution and therfore both, the Canon and Nikon extreme-zooms are a very good compromise even though they are lacking a bit in performance.
[/quote]
The difference at the 80mm focal length between both lenses, according to the MTF results, is small. So small, that probably in print one would not be able to tell which is which.
At 400mm focal length, the difference between the lenses is HUGE, in comparison.
I do not know why you feel they would "equal out".
Especially, since one usually does not buy a 400mm zoom to shoot at 80mm, one gets such a lens especially because of its 400mm reach (and the zoom part just ads flexibility).
Then there is the CA performance... the Canon has characteristically low CA, but the Nikon shows very high CA.
It seems totally reasonable and understandable to give the Nikon a lower rating, because of its loss of contrast and resolution at the long end. That is what the lens is being bought for.
Price/Performance.... the Nikon evidently does not perform as well. Optically , it disappoints at the long end. AF wise, it can't compete with the Canon's fast USM action. And its tripod collar did not at all impress the reviewer. Yet it is a bit more expensive. It does not say "Price", but "Price/Performance". It would be strange if the Nikon got a higher rating here, as it is not just about the price!
First of all I think that the reviews of PZ are an excelent and precise evaluation of lenses and I trust and use it all the time to make decisions to buy or not to buy a lens. So thanks for your great work so far.
But some of the coments and conclusions about the optical quality of the Nikon 80-400 in relation to the Canon 100-400 are in my view contradicting to your own MTF data for these two lenses. Comparing this data directly the Nikon shows a better MTF performace from the wide end to about 200mm and the Canon improves from than on to the far end at 400mm. In my view both lenses have their strong areas and their weeaknesses. Even if a comparison does not make real sense, because the lenses can not be used on the competitors bodies, I think 3,5 stars for the Canon versus 2 stars for the Nikon in "Optical Quality" seem not to represent your own MTF values and may not represent the true picture.
Strong and weak areas are about equal on both leses so in my opinion the number of stars for this category should be more or less the same. I can not judge on the Canon lens by experience, but I own and use the Nikon since many years. Generally I totally agree on what the data shows. The lens is quite a good perfomer between 80mm and 200mm and still okay at 300mm. At 400 mm it is definately lacking resolution and contrast. Looking at the MTF data the Sigma is no winner in any area and for that reason not an option for any of the two at all, but it did recieve more stars in the "Optical Quality" section, which I find a bit mislading to readers. Not that I have seen any test in the past were the Sigma outperformed either, the Canon or the Nikon. Also the "Price/Performance" section with 2 stars for Nikon ( around 1500 €) and 4 stars for Canon (around 1400 €} seems not to represent reality as for a very similar price there is a very similar perormace of both lenses with a lack in eiter end of the zoom range, according to your own MTF dataset.
For the ones who always point at the Nikon 200-400 they would get instead and which is clearly the performance winner. There are many jobs were weight and size matters so much more than resolution and therfore both, the Canon and Nikon extreme-zooms are a very good compromise even though they are lacking a bit in performance.
[/quote]
The difference at the 80mm focal length between both lenses, according to the MTF results, is small. So small, that probably in print one would not be able to tell which is which.
At 400mm focal length, the difference between the lenses is HUGE, in comparison.
I do not know why you feel they would "equal out".
Especially, since one usually does not buy a 400mm zoom to shoot at 80mm, one gets such a lens especially because of its 400mm reach (and the zoom part just ads flexibility).
Then there is the CA performance... the Canon has characteristically low CA, but the Nikon shows very high CA.
It seems totally reasonable and understandable to give the Nikon a lower rating, because of its loss of contrast and resolution at the long end. That is what the lens is being bought for.
Price/Performance.... the Nikon evidently does not perform as well. Optically , it disappoints at the long end. AF wise, it can't compete with the Canon's fast USM action. And its tripod collar did not at all impress the reviewer. Yet it is a bit more expensive. It does not say "Price", but "Price/Performance". It would be strange if the Nikon got a higher rating here, as it is not just about the price!