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17
votes
2answers
1k views

What makes the focus ring on a lens go smoothly?

I’m curious about the smooth movement of the zoom or focus rings on a lens. How is the smooth movement done? Is there some kind of liquid with high viscosity? That doesn’t sound very probable. On the ...
17
votes
2answers
831 views

Do rounded edges on aperture blades improve image sharpness, and how?

In the description for the XF lenses for its new X-Pro system, Fujifilm crows: The [XF lenses] all offer precise control over depth-of-field and deliver excellent out-of-focus bokeh thanks to the ...
13
votes
4answers
3k views

Why does a small change in focal length of two lenses make a $1000.00 difference in the price?

I was looking at some lenses and the famous 24-70mm f/2.8G ED AF-S Nikkor Wide Angle Zoom Lens is almost $2000.00. Then, I also found this one: Nikon 28-70mm f/2.8D ED-IF AF-S Zoom Nikkor Lens and ...
13
votes
4answers
679 views

Does Canon make an L series lens with a plastic lens mount?

An online retailer is telling me that Canon 24-105 f4L lens comes in two versions, the USA model with a steel lens mount and an import with a plastic lens mount. Is this true?
7
votes
1answer
321 views

What are the constructional differences between a macro and a regular lens?

I understand that to reduce minimum focusing distances, macro lens design must focus on maintaining certain distances between the lens and the sensor. However, is the placement of the lens and its ...
3
votes
4answers
163 views

How can the focal length of a lens be many times greater than the lens's physical length?

I bought a Tamron 16-300. Question is: how can it have a focal length 0f 300 mm when it is only about 30 mm long? Doesn't the lens have to be 300 mm from the sensing element?
3
votes
1answer
121 views

What is the reason that the materials of the lens barrels changed from metal to plastic?

Most of my older lenses have a shell of metal instead of plastic that is common today on all lenses even the expensive ones (with the possible exception of expensive tele lenses). When I compare the ...
2
votes
1answer
1k views

How does the quantity of elements and blades in a lens affect the optics?

I am trying to get a greater understanding of how lenses work. Basically I bought this lens, the Sigma 10-20 f4-5.6: The construction has really fascinated me. 14 Elements in 10 Groups?! What ...
0
votes
1answer
67 views

Can I remove the tiny amount of wiggle in the focus ring of my brand new lens?

I just purchased a Samyang 24mm T1.5 lens and the focus ring is not 100% solid and smooth, there is a tiny amount of give in the vertical direction (perpindicular to the horizontal direction the ring ...