Questions tagged [optical-quality]

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10
votes
5answers
2k views

How can these photos by Martin Schoeller have such a high quality?

Today, I ended up in a site showing famous people faces in a very first plane. I just got impressed by the quality those photos had. What do you think are the factors you have to tweak to reach that ...
11
votes
4answers
7k views

How many optical aberration types are there in lenses? And what are they?

Everyone hears something about chromatic aberration but are there any other types? What causes them?
9
votes
3answers
390 views

What are the standard tests available to quantify lens parameters?

In some of the questions I have asked here, some of the terms frequently used to describe the difference in image quality between the cheaper lenses and the premium ones have been increased contrast, ...
2
votes
3answers
570 views

Does the higher price lens always reflect better quality regardless of it being 3rd party or not?

When looking at various lenses you will see the camera manufacturer lenses made by the camera manufacturer. Then you will see other 3rd party lenses (Tamron, Sigma, etc). Does it pay to get the ...
5
votes
2answers
1k views

What's the base f-stop when counting an ideal f-stop for lens?

I've read a lot around this site that an ideal quality of the lens is achieved when using f-stop roughly 2 stops slower than the fastest value of the lens. Firstly, I'm not exactly sure what "2 stops"...
13
votes
6answers
8k views

Do lenses lose sharpness when they age?

I was reading this answer where it mentions, "..it's a lens that can lose sharpness as it ages.." and was wondering if this is true and if yes, true for all lenses. Reasons as to why this happens and ...
5
votes
2answers
158 views

Does “the same” lens, with different autofocus systems, have the same optical quality?

I'll give examples with Nikon only, but the question is pretty general. So, is this a fact or not? Examples: Nikkor 50/1.8G AF-S, Nikkor 50/1.8 AF-D and Nikkor 50/1.8 AF 70-300 AF and 70-300 AF-S ...
14
votes
4answers
755 views

How to rate the optical quality of a used lens?

I've read that you can examine a lens for scratches and defects by holding the aperture ring at its lowest setting and shining a flashlight through the lens. When I do this, however, a lot of stuff ...
17
votes
1answer
4k views

What is the “Newton Effect”?

I was just chatting with a photographer friend of mine, and he mentioned wanting "anti-newton glass"... I didn't know what that was, so I did a google search. I quickly figured out that it was ...
7
votes
5answers
4k views

How much different are the Tamron 17-50mm f/2.8 stabilized (VC) and non-stabilized versions?

I have seen these 2 lenses being suggested by many people across the site as general purpose zooms and an upgrade to the typical 18-55mm kit lenses. The price difference seems to be around $200 (~INR ...
1
vote
1answer
209 views

Can my copy of this lens (Pentax DA 18-135) have problems?

I'm struggling with this lens since quite a bit, and I'm not able to understand if the lens have problems or I'm expecting too much. Surely it has a problem: it's never consistent. I've got shots ...