Tagged Questions
5
votes
2answers
119 views
How can I quickly tell without testing if my lens is parfocal or varifocal?
I have read a couple of related questions, but I am curious to find out if there is a list of parfocal/varifocal lenses out there.
I'm most concerned with the lenses I have and I would like to know ...
6
votes
1answer
183 views
When focusing at max zoom, focus is lost after zooming out. Is that normal?
On my Canon kit lens, I could completely zoom in, focus on the object and then zoom out to take the picture with the object still in focus.
Now I have a Sigma 18-200mm (with a Canon 600D) and that ...
1
vote
2answers
131 views
What does it mean for a telecentric lens to be focused to infinity?
I have a question about a telecentric lens Ive been studying (for physics research!) and was wondering if you guys could help clear some cobwebs in my head. For starters, I am simplifying the TC lens ...
4
votes
2answers
130 views
Why do the Nikkor non-AI 135mm vs 50mm f/1.8 work differently when I look directly through the lens?
I recently purchased an old Nikkor 135 f/2.8 non-AI lens. Beautiful lens, but the closest focal distance is about five feet.
I noticed that it will 'focus' at about 4 inches as well. If I hold the ...
3
votes
2answers
734 views
What does “Flat Field Focus” mean?
Looking at lenses, specifically sigma macro lenses, I noticed that it had a ""Flat Field" front lens element". What does this mean? And how is it different to the norm?
2
votes
2answers
192 views
Why is my lens focusing sound lounder than before?
I'm new to DSLR camera. I didn't mount a lens properly. The camera still allowed me to take photos, so I didn't notice the error.
After I had been using it for 10 minutes I noticed my error and ...
8
votes
3answers
518 views
Easier ways to pre focus a distance on a lens without manual focusing meter?
In applying zone focus(focusing at particular distance in advance, before the subject comes in) to shoot a bike that will come into frame, how do I correctly focus at a particular distance with a lens ...
3
votes
2answers
562 views
All my photos were blurry
I recently did a shoot of a baby and my 6 year old son, and I got some fantastic shots that were super sharp. I then did another shoot of a 6 year old and toddler and every single photo was slightly ...
13
votes
2answers
548 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 ...
4
votes
4answers
292 views
How can I make close-by objects appear as if they were much bigger?
We all know the popular Tilt Shift technique that gives objects a "miniature" look, making them appear much smaller than they actually are.
I'm wondering whether it's possible to achieve the opposite ...
6
votes
3answers
738 views
What are “Depth of field and focus scales”?
I'm reading Kurt Munger's review of SAL75300 (Sony's 75-300mm F/4.5-5.6 lens) and I noticed the entry "Depth of field and focus scales? Nothing" in his summary table. Now, I know what depth of field ...
6
votes
4answers
2k views
Is it difficult to focus on 1.4F prime lens, and if it is how to counter that?
Does difficulty in focusing have anything to do with 1.4F (Nikon G)?
Will it be still difficult if I use manual focus?
Is auto focus too slow?
Is there a way to counter it?
This example photo (from ...
2
votes
2answers
229 views
How can I find which lenses have “Continuous manual focus”?
Canon lenses with USM auto focus can be called "continuous manual focus" (at least some). By this I mean that you can override the AF without switching it off. I've found this very handy, and I often ...
4
votes
2answers
631 views
Is it normal for focal length to change while focusing?
When I change the focus distance on my Pentax 55-300mm lens, the focal length appears to change. More specifically, the lens appears to zoom in as I focus towards the minimum focusing distance. This ...
7
votes
4answers
1k views
How can I get maximum DoF with no distance markers?
I am aware of what hyperfocal distance is and the general principles behind it. However, most of the tutorials I have seen and read regarding it make use of lenses with focus distance indicators. ...
12
votes
2answers
570 views
Does a crop sensor affect closest focusing distance? Why does it not affect focal length in EXIF data?
Since I am considering to buy the Nikkor 105mm micro VR, I wondered if the cropped sensor does affect the closest focusing distance of 0.31m?
Thinking about this, the following additional (and ...
10
votes
1answer
2k views
What is a focus limiter?
What is a focus limiter and how does it work? What is the advantage of it? For instance Tamron 90/2.8 Macro has a focus limiter. According to the documentation:
In the limit position, the Tamron ...
12
votes
4answers
620 views
How close can a lens focus?
From my understanding, if you want to do some macro photography it is better to have a lens that can focus when it is really close to the subject. Sometimes people buy extension tubes to help them ...
6
votes
2answers
187 views
Can a hard impact foul up a lens' focus?
Recently, a camera with lens attached got knocked off a chair and hit the floor (not my gear, fortunately!). Following that, the lens would not focus properly, either with manual focus or auto. The ...
20
votes
3answers
5k views
How can a 18-55mm lens focus on objects beyond 55mm?
I guess this is a total noob question, but doesn't 18-55mm mean that it can focus only up to 55mm?
18
votes
2answers
998 views
Why am I allowed to turn my focusing ring beyond infinity?
Is there a good reason why I can turn the focusing ring on my lenses beyond infinity mark on focusing scale? Following recent questions here and here, it sounds like a real usability issue.
...
24
votes
4answers
21k views
What is back-focusing?
What is back-focusing? Is it something I need to be worried about, or can I just live with it? How can I tell if my camera/lens is sufferring from it?
24
votes
6answers
3k views
Can I damage the focus system by turning the focus ring when the lens isn't mounted?
I have a couple lenses that don't have an internal focusing system, and whenever I want to put them back in my bag, I turn the focus ring to make the lens shorter.
I noticed that when the lens is set ...
