Questions tagged [aperture]

Aperture is the opening in the diaphragm of a camera lens. For questions relating to Apple's photo management software, please use [apple-aperture] instead.

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57 votes
9 answers
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What is aperture, and how does it affect my photographs?

How does aperture affect my photographs? Why should I care about the aperture with which a photo was taken?
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25 votes
9 answers
7k views

Can a smaller sensor's "crop factor" be used to calculate the exact increase in depth of field?

If APS-C and similar crop-sensor digital cameras have a focal length multiplying effect such that a 50mm lens has an apparent focal length closer to the field of view of an 80mm on a full frame camera,...
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68 votes
7 answers
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What is a "diffraction limit"?

I've seen the term used, but what is a "diffraction limit", when should I worry about it, and what undesirable effects are a result of it ?
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12 votes
4 answers
8k views

What is the relationship between ISO, aperture, and shutter speed?

I know digital cameras have ISO options, and that ISO is the camera's sensitivity to light, but if you set higher ISO then you can get a noisy image. I also know there are two other camera options, ...
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25 votes
4 answers
3k views

Do smaller apertures provide more depth of field past the diffraction limit, even if peak sharpness suffers?

In Understanding Exposure (3rd edition, on page 48), Bryan Peterson has what might be called a rant against modern on-line conventional wisdom about diffraction limits. Answers on this web site are ...
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68 votes
4 answers
153k views

What does f-stop mean?

What does f-stop mean? Is it the same thing when people say "2 stops" for example?
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32 votes
2 answers
26k views

What is T-number / T-stop?

Usually, when discussing aperture of a lens, F-stop and F-number are used for quantifying. But some photographers, and especially videographers, also mention T-stop. The concept and numbering used (e....
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29 votes
2 answers
4k views

Why use a small aperture when trying to see sensor dust?

Here and there I read of people who set their lens to a small aperture while testing their sensor cleanness, supposedly to get the best image of dust speckles. However, the image of the on-sensor dust ...
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36 votes
8 answers
28k views

Technically, why is the out of focus area blurred more when using a bigger aperture?

I'm wondering, technically, why and how does the out of focus areas blur more when using a bigger aperture. I think it'd help a lot if I presented a problem that's been driving me nuts for a long time:...
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26 votes
5 answers
7k views

Why is the depth-of-field preview in the optical viewfinder of my Canon 500D inaccurate?

I have noticed that in my Canon 500D, the depth-of-field preview in the optical viewfinder is inaccurate with large aperture settings. If I press the DoF preview button, there is very little ...
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36 votes
4 answers
8k views

How do you find out the "sweet spot" of a lens?

I've tried googling this, but have never found a satisfactory answer. I've heard the term "sweet spot" thrown around by some photographers to mean the f-stop of a lens which results in the highest ...
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45 votes
7 answers
12k views

How do constant aperture zoom lenses work?

Cheaper zoom lenses usually are faster at the wide end and slower at the long end (for example, the $150 Canon EF-S 18-55mm f/3.5-5.6). More expensive constant-aperture zoom lenses have the same ...
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21 votes
4 answers
7k views

Do the same camera settings lead to the same exposure across different sensor sizes?

Let's say I have a micro-4/3rd camera and a full frame camera, both set to 1/60 at f/2.8, taking a picture of the same scene in the same lighting. Will the exposure be the same across both cameras ...
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20 votes
2 answers
5k views

Why do zoom lenses and compact cameras have varied maximum aperture across the zoom range?

Why does a camera's maximum (allowed) aperture get smaller when you increase its zoom?
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22 votes
7 answers
13k views

How can aperture be f/11 on a lens with an aperture range designation of 3.5-5.6?

I made a series of outdoor shots with Nikon D5000, with the 18-55mm 1:3.5-5.6G VR kit lens. On some shots, I see in the EXIF info f/11, and in another shot, f/9. How can that be, that the f-number ...
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  • 1,057
25 votes
4 answers
6k views

What is a "fast" lens?

I've been reading lots of camera reviews lately and have ran across several references to "fast" lenses. What exactly is a fast lens and what are its advantages compared to other lenses?
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12 votes
7 answers
107k views

Why is my Nikon 50mm f/1.8 giving me an fEE error?

I have a AF Nikkor 50mm f/1.8. When I have the aperture setting on the lens to 22 I can take photos. But when I change the dial to anything other than 22(lowest f/stop) then I get a flashing fEE ...
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48 votes
5 answers
39k views

What apertures are required to enable autofocus, including cross-type or high-precision focusing, on Canon DSLR cameras?

This is a follow-up to Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers? I'm doing this to separate the AF aperture requirements from the linked question above. My goal ...
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  • 5,756
14 votes
3 answers
2k views

How do zoom lenses restrict their widest aperture at the telephoto end?

Does the aperture ring lock the apertures beyond, say 5.6 at length lens's telephoto end? Does the lens introduce an obstacle to the aperture ring so the lens can't be opened anymore beyond the ...
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  • 1,475
16 votes
2 answers
4k views

How do DSLRs figure out what aperture to select in P mode?

In program mode, DSLRs adjust not only the ISO and the shutter speed, but also the aperture. The aperture has a huge impact in some situations. For example, when shooting a close subject in front of ...
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4 votes
2 answers
4k views

Is the size of the entrance pupil the same as the size of the effective aperture?

I understand that the entrance pupil is the image of the aperture as seen from the front of the lens. However, is the size of the entrance pupil the same as the size of the effective aperture? In ...
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28 votes
10 answers
84k views

What is an easy way to remember the full stop scale?

If you were teaching someone new to photography the full stop scales, is there a better way then flat out memorizing these values? Does anyone have an easy way that they remember the scale? Would it ...
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70 votes
12 answers
90k views

Is there a noticeable difference between 1.8 and 1.4 prime lenses?

I have been shopping around for a prime lens for my Nikon D50. I noticed that the 1.8 is hundreds of dollars cheaper than the 1.4 AF-S. What will I gain for that cost difference? Is it really ...
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9 votes
4 answers
3k views

Why is the background bigger and blurrier in one of these images?

On my EM-10 Mk2, I'm testing a Panasonic 25mm f1.8 (top image) against the 20mm f1.7 (bottom image). I tried to make the lamp take up the same space in the frame before focusing, yet the background ...
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36 votes
10 answers
4k views

What are some tips for shooting in low light?

I own a Canon 450D with just the standard kit lens that comes with it (I don't plan buying a new lens for a while) and one thing I tend to struggle with is shooting in lower light conditions, indoors ...
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29 votes
3 answers
8k views

Why do wide angle prime lenses have relatively small apertures?

I've noticed that many of the wide angle prime lenses (at least for Canon) have somewhat smaller apertures than their normal or telephoto counterparts. E.g. the regular Canon 24mm prime is f/2.8 while ...
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10 votes
2 answers
30k views

Why does my aperture setting change as I zoom on my DSLR kit lens?

I am new to the photography field, there are few things which I am not able to understand. I am playing around with my Nikon D90 along with its kit lens (18-105mm). While reading about Depth of ...
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11 votes
3 answers
6k views

What are the theoretical minimum and maximum apertures?

Is there such a thing as a maximum aperture that a lens can be open to? What about a minimum aperture that it can be closed to? Do these concepts even make any sense? Is there a lens with the ...
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6 votes
7 answers
23k views

Do I use the crop factor in calculating aperture size and area?

How do I calculate the aperture size and area, considering an 35mm equivalent focal length value and non-equivalent aperture f-number (in terms of exposure, no multiplication of the crop factor of the ...
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3 votes
2 answers
4k views

What's the difference between real and effective aperture?

I understand that the simple idea that f-stop is focal length divided by aperture really applies to a simple single-glass lens, not the compound lens systems used to provide good image quality in ...
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14 votes
6 answers
11k views

What is the meaning of "stopped down"?

Was reading this answer (emphasis mine): It also tells us that the lens was stopped down, as if it were wide open there would be no corners to cause diffraction, regardless of the number of ...
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23 votes
7 answers
10k views

Why don't compact digital cameras have the aperture range of DSLRs?

Why is it that on compact digital cameras the aperture never seems to go any smaller than about F8 ? Even on high-end compacts such as the Canon G10 or Panasonic LX5. Is there some practical or ...
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31 votes
7 answers
7k views

When to use shutter priority instead of aperture priority?

Under what circumstances would you use aperture priority vs. shutter priority and vice-versa? I typically don’t use shutter priority (ever) and favor aperture priority to try to get a max aperture ...
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8 votes
4 answers
6k views

What are the advantages of a lens having a fixed maximum aperture?

What are the advantages of a lens having a Fixed Maximum Aperture? Previous answers have indicated that "pros tend to want constant apertures in zoom lenses". While in general lenses with a fixed ...
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14 votes
4 answers
9k views

Does using an extender actually change the aperture of the lens?

I just bought a Canon 2X extender and I always believed that it would only result in 2 stops' loss of light and not change the aperture. However, when I tested this extender on a Canon 135mm f/2 ...
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11 votes
8 answers
9k views

What is the fastest lens available for a DSLR?

I've seen references to f1.2 lenses. I was wondering, are there any faster lenses available for a DSLR mount?
7 votes
5 answers
2k views

What are the benefits and costs of an image stabilized, slower lens vs a non-IS faster lens?

I am going thru a trade off decision between a 24-70 f2.8 lens and a 24-105 f4 IS lens from Canon. My dilemma is that the 24-105 focal length better matches my needs, but the f2.8 would occasionally ...
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0 votes
3 answers
11k views

Why do I get the "Press Shutter Release Button Again" error when my D3200 isn't set to max. aperture?

I know there are quite a few posts out there about the famous "Press Shutter Release Button Again" error. But mine seems to be quite weird. I own a Nikon D3200 with the standard 18-55 mm lens. It ...
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45 votes
4 answers
8k views

How does aperture work without "cropping" the image hitting the sensor?

I've been teaching myself the various settings in cameras and now have a much fuller understanding of how to use my camera effectively, but one thing is still bugging me. When the aperture size is ...
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12 votes
3 answers
9k views

Why don't comparisons of aperture take sensor size into account?

When one compares focal length, many times we use the 35mm equivalent length. A 50mm lens on an APS-C sensor camera(1.6x) would be a 80mm equiv. length on a full frame camera. But when we state the ...
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4 votes
1 answer
2k views

Does maximum aperture change with focus distance with the Canon 60mm f/2.8 macro lens?

This site says The Canon EF-S 60mm f/2.8 Macro USM Lens loses 1/2 stop at 1:5, 1 stop at 1:3, 1.5 stops at 1:1.5 and 2 stops at 1:1 (lifesize). Can anyone confirm that at 1:5 magnification, the ...
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15 votes
9 answers
3k views

Would a prime be redundant with a fast zoom?

Now that I am finally getting a fast zoom (Tamron 17-50mm 2.8) I've been considering a fast prime to go with it, specifically a Sigma 50mm 1.4. Despite its shortcomings, it still does really nice ...
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2 votes
1 answer
6k views

Can I control the aperture of a F-mount lens with aperture ring from the camera body?

If I buy a lens with a manual aperture ring like the Nikon AF 50mm f/1.8D, then does that mean that I can only control the aperture on the lens? Or can the camera control it too? I want one with ...
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2 votes
2 answers
2k views

Nikon D7000 thinks aperture of non-cpu lens is always 16 and overexposes photos

I have a non-cpu lens with manual aperture control (I use the aperture ring to set it, and it stays that way when I shoot). My D7000 used to work fine with this lens in A mode - all images were ...
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  • 123
1 vote
2 answers
3k views

How to lock aperture using Reverse ring with Canon 600D?

Is there anyone using reverse ring and know how to lock the aperture. I tried doing the techniques provided on youtube. First connecting the lens on original positions then lock the aperture by ...
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  • 113
17 votes
2 answers
14k views

Why does Canon and Nikon limit or disable autofocus beyond certain f-numbers?

One thing that I've noticed with Canon DSLR camera is they will disable or limit autofocus when the lens' maximum aperture is narrower than certain values, which are specified in my answer to What ...
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  • 5,756
9 votes
1 answer
4k views

How can the aperture value written in Exif be larger than the nominal limit of the lens?

A photo shot with an 1:1.8 lens contains the following exif data: ApertureValue: 1695994/1000000 MaxApertureValue: 16/10 How is this possible? Both values are <1.8.
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14 votes
5 answers
1k views

Why are only certain shutter speeds or apertures available?

For the exposure control function DSLRs there are specific shutter speeds available. For example there are 1/4, 1/100, 1/500. Why, even in high end DSLRs, is there no option to use a custom shutter ...
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  • 351
8 votes
5 answers
2k views

How do different aperture and shutter settings affect a photo with the same overall exposure?

Ok, here's my doubt. Suppose I want to get a certain exposure for an image. Keeping the ISO constant, there are two tentative possibilities here: Put the camera at f 1.4 (say) and at 1/1600 shutter ...
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  • 1,300
17 votes
8 answers
9k views

Will using a lens at max aperture ("wide open") result in poor images?

I’m looking to add a second lens to my kit lens I got with my Nikon D7000. I have read several reviews on both the 35 and 50 mm lenses made by Nikon in particular that said using either lens at the ...
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