Road Train !!!!!!!!!!

by Russell McMahon

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0
votes
1answer
65 views

what is the barriers of making fast lenses? [duplicate]

I know there are lenses like f/0.7 However as a beginner I'm wondering what's the barrier of making ultra fast lenses like f/0.01 ? Also if lens manufacturers willing to make wide aperture lenses, ...
3
votes
4answers
163 views

Are the aperture, ISO and shutter speed stops perfectly interchangeable? [duplicate]

Imagine you have an scene with shutter speed 1/60, f/8 and ISO 200. Then you change the configuration to get an equivalent exposure: speed 1/120, f/5.6, ISO 200 (plus one stop in speed, minus one stop ...
6
votes
4answers
640 views

Is f/number more relevant than aperture and/or shutter speed?

I've seen on Flickr that the photographers specify values for four settings about their photos (where exif data is available) - Shutter speed F number ISO Focal Length An example can be found ...
2
votes
1answer
196 views

What is the largest aperture on a commercially available lens? [duplicate]

Out of pure curiosity, what is the largest aperture, or lowest f-stop, a commercially available lens has. I have seen the 50mm prime lens from canon with 1.2, but not lower than that. What are the ...
9
votes
2answers
471 views

When using an Extender, does it 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. When I tested this extender on a Canon 135mm F/2 lens, the ...
7
votes
2answers
582 views

Do lenses with the same f-stop but different focal length gather the same amount of light? [duplicate]

I'm taking images of a light source in a scientific labratory, and I thought I had a good grasp on all these things, but now i'm second guessing myself after some results. The most important thing is ...
3
votes
2answers
482 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 ...
3
votes
1answer
299 views

How do I properly understand what f-stop is? [duplicate]

I don't quite understand why most lenses seem to have approximately the same diameter aperture regardless of focal length. F-stop is, by definition, a ratio of focal length to diameter, so a 20mm ...
15
votes
2answers
794 views

Does a specific f number across all lenses denote same amount of light?

When we say a light source emits 1500 lumens of light, it does not really matter if the light source is incandescent, CFL, diode etc. Similarly, when I say f/1.8 can I assume that all lenses pass the ...
10
votes
2answers
949 views

How to stop a high F number from appearing blurry?

I have been out taking some evening photos (just after sunset) and I have noticed that in a number of instances the higher f numbers ( 14+ ) are appearing more blurred than the lower f numbers ( < ...
2
votes
2answers
384 views

Why are the area of aperture, focal length, and amount of light specified in these terms?

So I'm looking at the wikipedia article on Aperture, and I'm a bit confused. I understand aperture to be the diameter of the hole that lets light in. In the article, someone states that The ...
8
votes
3answers
428 views

What is the limiting factor in lens construction when it comes to f-stop values?

This widely praised Nikon 105mm macro lens has a maximum f-stop value of 2.8. I've held it in my hands, it's a big lens. Meanwhile, this 50mm Nikon lens can go up to f/1.2, despite being 25% cheaper ...
13
votes
5answers
670 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 ...
18
votes
9answers
18k 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 ...
5
votes
4answers
11k views

What shutter speed to use when shooting video?

My camera is Canon 60D and I will be using it to shoot a short parkour video, that means: a lot of motion, moving subjects, moving camera focal length usually from 24 mm to 75 mm, but there will ...
16
votes
5answers
2k 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 ...
20
votes
4answers
3k views

Why do compact digital cameras not 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 Cannon G10 or Panasonic LX5. Is there some practical or ...
0
votes
2answers
387 views

True or False: A two full F/stop change to either side of the starting F/stop will either double or half the amount of light from the original F/stop

Explain. A two full F/stop change to either side of the starting F/stop will either double or half the amount of light from the original F/stop.
5
votes
7answers
1k views

Is there any way to stop down the aperture of a Canon PowerShot SD780 IS?

I have a Canon PowerShot SD780 IS point-and-shoot which I use as my carry-around-everywhere camera when I don't want to drag my SLR about. This tiny little camera works great and takes fabulous ...
24
votes
4answers
3k 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 ...
51
votes
3answers
31k views

What does f-stop mean?

What does f-stop mean? Is it the same thing when people say "2 stops" for example?