18 replies to this topic

[deano]

I shot the attached photo with my new D750, using a new Sigma 24-105 lens

I opened it in DxO, saved as a tiff, transferred to Lightroom.

I shot the photo in both raw and jpeg.  Both formats give me the same blurry detail in the wall mural

Please look at the far right corner of the wall mural.  It appears to be blurry, while the middle and right side are in focus.

data: 1/640 24mm @ f16, -1ev, iso 200

If you can enlarge the photo on your commuter, maybe you can see what I mean.

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[Nikonite]

I don't see an attached photo deano?

[deano]

Just loaded it.  I tried to load it as a tiff, that is a no no, so I saved it as a jpeg and was able to load it.

[Nikonite]

I did as you suggested and downloaded it to my PC. I then enlarged it to try to see what you see. I think what you see is only noticeable at full resolution. Downloading from this site and then enlarging it becomes pixilated long before you can see detail. That said my old Nikkor 18-200 had terrible fall off on the corners at 200mm, but as I said that was only noticeable at full resolution. When I down sized for the web it was only visible to a trained eye.

[deano]

I use a mac with a 24 inch screen.

I will take some more shots tomorrow at the Veterans Day parade and see what I get.

Thanks for the help.

[Nikonite]

I use a PC I built myself with a 4k 27" monitor. The monitor is fabulous to a fault. It shows every little detail.

[dcbear78]

Out of interest what monitor do you have? Trying to decide between 27" 4k screen or one of the new 34" 21:9 screens.

[Nikonite]

Asus PB287Q. Love this monitor!

[deano]

My Mac desktop is one year old, and is listed in the specs as Late 2013

The monitor information says it is a 27" (2560 x 1440)

 

It has never failed me for clarity and color.

[Nikonite]

Oh yeah the Mac Monitors win all the comparison tests. I just question if they are worth their premium price. Because in those comparisons it's a light measuring device that gives the Macs the win. My eyes are just not as good as a light measuring device. Therefore in the store when I compare them side x side with the same image and I can't tell a difference I take the less expensive option. But that's just me.

[dcbear78]

New Mac monitor is 5k resolution!

[Merco_61]

I have never used the 24-105, but Gordon Laing at Cameralabs has tested it here. The field curvature that he mentions is probably what you see here. Such loss of sharpness and definition often disappears when resampling for the web, which explains why we don't see it.

[Nikonite]

As it is now except for still photography there is barely any 4k material. Is there any material for 5k?

[Serge]

f/16 - this is the answer to your detail loss. Lenses are usually the best at f/8 - f/11max  - further stepping down decreases IQ. In general only macro lenses are designed for small apertures. Use A program, ISO 100 and set your camera to f/8 - you will see the difference.

[Merco_61]

f/16 - this is the answer to your detail loss. Lenses are usually the best at f/8 - f/11max  - further stepping down decreases IQ. In general only macro lenses are designed for small apertures. Use A program, ISO 100 and set your camera to f/8 - you will see the difference.

Diffraction can be a problem, and probably is in this case. The other problem is a lens that has a field curvature that does not go away until f/11 or so at the widest focal lengths. The D750 is diffraction limited from about f/5.6 if my math isn't totally wrong as the airy disk gets significantly larger than the pixel pitch.

[deano]

Thanks everyone.  I will go back to the same location and retake, and repost for revue.

[deano]

I went back to the same location early this morning and good a few photos with the changes suggested.

By setting the f-stop at f8 the blurriness in the extreme right corner has diminished.  Also, I took photos with my 50mm @ f8, and my 105 @ 2 f8,  and have degrees of the same blurriness.  With the 24-105, setting at f9 the blurriness starts to increase.

The attachment is with the Sigma 24-105 @ 28mm and @ f8

Look at the lettering in the auto shop sign.  It appears less blurry than the first photo.

My big question is:  Does the Nikon 24-70 do a better job in the corners (or overall) than the Sigma?  

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[deano]

Peter, I just read the CameraLabs report on the Sigma 24-105 lens.  And yes, the falloff in the corners is inherent in the lens.  But overall it gets a good recommendation, one notch below the Nikon 24-70.  The Sigma has VR and the Nikon does not.

 

By the way, I am in Mexico next week for a bike race so will be out of touch for the week, so I will not be contributing to the challenges through this time.

[Dugit57]

On your original shot, it appears that the steel roof just above the wall is the actual focus point. There is a an adjustment on the 810 to dial in each lens optimally.