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Help requested: how to compare 2 similar lenses? (maybe 3)
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PostPosted: Fri Oct 31, 2014 4:52 pm    Post subject: Reply with quote
Gerald. I assume you are using a tripod for the test. Do you found any difference in sharpness when the VR mode change from ON to OFF at 140mm?


PostPosted: Fri Oct 31, 2014 5:04 pm    Post subject: Reply with quote
calvin83 wrote:
Gerald. I assume you are using a tripod for the test. Do you found any difference in sharpness when the VR mode change from ON to OFF at 140mm?


Yes, I used a tripod and VR was OFF.
I didn't test with VR ON. Do you think it would make a difference?

Edit:
exposure times for 140mm:
F5.6 0.8 sec
F8 1.6 sec
F11 2.5 sec
F16 5 sec
F22 13 sec

other conditions: ISO 100, self-timer 10s, A mode, +1EV, 200W incandescent light, WB pre-set


PostPosted: Fri Oct 31, 2014 5:29 pm    Post subject: Reply with quote
Gerald wrote:
calvin83 wrote:
Gerald. I assume you are using a tripod for the test. Do you found any difference in sharpness when the VR mode change from ON to OFF at 140mm?


Yes, I used a tripod and VR was OFF.
I didn't test with VR ON. Do you think it would make a difference?

I see. When camera/lens is mounted on a secure tripod, setting the VR ON will reduce the sharpness if the lens does not have tripod detection.

From the manual of 18-140 VR:
Quote:
Select OFF when the camera is mounted on a tripod unless the tripod head is unsecured or the camera is mounted on a monopod, in which case ON is recommended.


PostPosted: Fri Oct 31, 2014 6:52 pm    Post subject: Reply with quote
Perhaps it is of interest to see what happens in the wide angle department. The Nikkor at 18mm corresponds to about a 27mm lens for full frame, so I compared the Nikkor performance with a Tamron 28mm F2.8 and a Pentacon 29mm F2.8. Before someone comments on the results, I would say that all the lenses are in perfect order and do not suffer from decentering, so I believe the results are representative for these lenses.

The 100% crops are from the upper left corner. The apertures used were F3.5 and F11 for the Nikkor, and F4 and F11 for the other lenses.







Wide angle lenses traditionally have great difficulty in providing sharpness in the corners, especially for wide open condition. The performance of the Pentacon 29mm at the extreme corner follows the usual pattern of many old retrofocus wide angle lenses: the performance is quite poor for wide open, but gradually increases until it reaches the maximum at F16. Interestingly, the peak performance of the Nikkor occurs about the maximum aperture!

It is clear that the Tamron cannot match the Nikkor at the corners, but the Tamron performs significantly better than the Pentacon.

If the results at corners can be a little scary, the performances in the center are much more civilized, as shown by the 100% crops for F3.5 (Nikkor) and F4 (Tamron and Pentacon). After F5.6 the performance in the center are more or less the same.



EDIT: I wanted to add that the distortion of the Nikkor at 18mm is very ugly, and much worse than the Tamron and Pentacon. On the other hand, the D5300 and other Nikon cameras automatically correct distortion if Auto Distortion Control is set to ON. In the tests, the distortion was not corrected. The photos were captured in RAW and converted to JPEG with ACR with sharpening control set to zero.


PostPosted: Sat Nov 01, 2014 4:09 am    Post subject: Reply with quote
The result on DXO shows the 18-140 VR in a D5200 have best sharpness at F4/18mm http://www.dxomark.com/Lenses/Nikon/Nikon-AF-S-DX-NIKKOR-18-140mm-F35-56G-ED-VR-mounted-on-Nikon-D5200__850 .

Most standard kit zoom for APS-C and M4/3 have better performance at the wide end than the tele end. The performance on the wide end(1xmm to 21mm) is much better than the budget old wide angles. Unlike the budget old wide angles, the peak performance of these kit zoom is obtained at full open or near full open . open This is the reason why I always recommend the kit lens when someone asked a budget wide angle for their APS-C and M4/3 camera.
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