Zoom or Prime, Nikon or Sigma

[ilkka_nissila]

I don't think the comparison is that bad. To do lens testing you'd choose a stationary subject, use a tripod and make sure all the conditions are the same. But the difference between an 85 mm Nikkor prime and a 24-120 zoom are significant enough to show on any shot, so why not show a practical example. Although the JPEGs are small, they obviously show only a tiny part of the full frame, and so you can see differences in rendition of detail. And as for aperture, if you hand-hold a 120/5.6, you're very likely to hand-hold it at f/5.6. That's why these lenses aren't so great, because they have max apertures that force you to shoot wide open quite often. With a 85 prime, f/5.6 is probably the optimum aperture, so you get good results. The comparison is fair because in real world (outdoors) you can't just turn on the lights to be able to stop down the zoom.

[martin_jiang1]

Guys

 

What's with all those self-rightous answers? I am not here to get into a debate as "How to test a lens", rather "Is my 24-120mm VR a OK one?".

 

"It is essentially meaningless to compare small JPEGs." Sir Mr. Tif guy, do you understand relative comparison? Do you understand that a digital SLR require a lot more optical quality than a film SLR? And finally do you understand that this is 1:1 actual pixel cropped from a large image? Please go back to learn some basic before dropping a two line junk here that serves no purpose than your ignorance.

 

For the rest of guys, I thank you for your candor and suggestions, but my inital reason to do such test is to see if my 24-120mm suffers the first batch Nikon quality problem regarding the softness. If you guys are shopping for the saem lens, then you would know that a batch of this lense has a serious softness problem and I just want to make sure mine is not in that batch. In other words, whether the softness displayed in this picture is acceptible or defective. Let me say again, I am not here to try to say the 24-120 is as sharp as the 85mm, but rather to show how much difference that is, why would that rub someone the wrong way just puzzles me....

 

Anyway, peace out and back to dpreview.com

[ShunCheung]

Martin, when you compare lenses, you need to compare center against center, edge against edge, you need to see the entire image with straight lines near the edges to see distortions .... A lot of mediocre zooms may be ok in the center but suffer near the edges, they may be ok at f8 but are poor wide open, etc. etc.

 

In other words, what you have presented here is far from complete and IMO very insufficient to judge those lenses with. You'll need samples from center and edge at a few different apertures for a thorough comparison. At f5.6, the zoom is almost wide open while the 85mm is 3+ stops down. Nobody should be surprised that the prime is better. At f11, the difference may be a lot smaller.

 

By the way, if you disagree with me, that is perfectly fine, but please stay civil in this forum.