Why is Aperture priority preferred over Shutter priority?

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panerai

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I thought a set shutter speed sets the aperture to a set f stop or so I read in Understanding Exposure (still reading it)

F4 is 1/500 and F5.6 is 1/250 etc. based on ISO 100 film

Or is it there's more possible problems with the mechanics of shutter priority models

Thanks

DON
 
Two reasons.
It's easier to design and manufacture the mechanism to control the linear movement of a shutter mechanism than the rotational movement of an iris diaphragm. Especially where interchangeable lenses are involved.
And most people prefer to have primary control over the aperture to allow use of the depth of field effect.
 
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I almost always prefer to have direct control over my aperture setting so I can regulate depth of field. Its only occasionally that I am more worried about shutter speed (assuming its within a normal shooting bandwidth) This is when I am shooting sports or similar. At the end of the day it does not really matter of course as the two are interlocked (one goes up - the other goes down) but it makes it easier to control aperture directly if that is what you wish to do. For this reason I will often set my DSLR on A not P or S.
 
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Because aperture priority respects your decision on depth of field or selective focus. Shutter priority doesn't...

A given aperture defines an image a lot more than a given shutter speed.

Cheers,

Juan
 
If i'm in a fast-paced shooting environment I may select Aperture Priority so I may control DOF, as has been said.

If i'm out having a few drinks and taking photos, i'll set the camera to Shutter Priority and select the appropriate shutter speed to account for my balance impairment ;)
 
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What everyone else said and about the only exception is when I take photos of propeller driven aircraft. I want prop blur in that case so shutter priority is used to keep 1/125.

Bob
 
Note that most responders so far talk about the depth of field aspect of aperture selection. Depth of field and control of the focus plane is one of a photographers most important tools in creating an image. Certainly there are subjects and conditions with which using just the right shutter speed for stop motion or blur effect is more important than d.o.f.- such as the prop plane pictures mentioned above- but for the majority of images, most photographers will tell you that depth of field is the more important aspect to control to get the image they want.
 
Thanks >>

Thanks >>

I have a Yashica GX and a Konica S2 and was looking to add a Konica auto s3 or Vivitar es35 just to play around with.

Also have my Panasonic LX3

DON
 
I think that book has confused more people about reciprocity than any other single source. No, a given shutter speed does not set a specific aperture. If you set the shutter speed, and use shutter priority auto-exposure, you camera will pick the aperture so that you get an average exposure - depending on how bright the scene is!

Likewise, with aperture priority, you can set the aperture and the camera will pick the "correct" shutter speed for an average exposure (neither mostly white, nor mostly black, but (as the third bear said) just right.

A lot of photographers like aperture priority because in addition to limiting how much light gets in through the lens, the diaphragm also changes how the picture looks. You hear a lot about "bokey" these days. That effect is aperture dependent - a large aperture makes the background more blurry, while a small opening in the lens makes the background sharper.

People who shoot action often prefer shutter priority, as a fast shutter speed takes less time, and "freezes" motion better. A slow shutter will show a blur where moving things are.

So it depends on what you want your photograph to show when you decide what kind of auto-exposure to use.
 
Add a Canon QL17 instead. Less expensive and has easier to handle than the two you mention IMHO. Crispy sharp lens as well.
 
Thanks again >>

Thanks again >>

Right now I'm testing the Yashica, but figure the seals are going. After I want to check out my dad's Konica which I found and in mint condition (with the mercury battery still good and clean - no leakage)

I did all the reading on the various Yashicas, Minoltas and Canon models and it was a toss up between the Yashica GX and Canon QL17, but seem to read about more problems with the Canon than the Yashica, so bought that model

Still playing around, reading the forum posts and learning little bits here and there

Regards

DON
 
For me there is an additional benefit to Aperture Priority vs Shutter:

Even when I want to affect shutter speed, I rather do so in aperture priority mode because I find that access to the the diaphragm ring is more convenient than turning the shutter dial on top of the camera.
 
Obviously, you trade off aperture vs shutter to maintain the correct exposure. There are certain specific circumstances where you want to choose shutter speed: blurring waterfalls 1/8 or less, not blurring bird wings, or freezing athletes in motion where you need 1/1000 or more. There are other specific circumstances where you want maximum or minimum Depth of Field, as long as your shutter speed is in the proper range, let's say faster than 1/125 to avoid blurring people who are walking.

The third knob is ISO. On film we wouldn't dial ISO around on every shot, but on a fully automatic, digital camera, you set aperture or shutter and the camera will optimize the other two parameters via some algorithm.

That gets confusing; well, for me it does, as I'm not very good at keeping track of three parameters. I admit that my photography would be much improved if I spent a year with a manual, film camera, (maybe a Leica as suggested by Mike Johnston at TOP) in order to gain better understanding and control. From Juan V's comments I get the feeling he has done exactly that.
 
Huh.... I can't recall a single time that I've ever used shutter priority. If I need to slow down movement of something, I usually just have the camera in manual... AP is the only other mode I use, and that's just for street work.
 
I agree with the above... I find that changing the aperture makes more of a tangible difference to my results than changing the shutter speed for what I photograph. For a mid-distance slow moving subject, choosing f5.6 over f2 will affect the result much much more than choosing 1/60 over 1/1000... so aperture priority would be appropriate. The 11th century church isn't going to move and I want it all in focus.

For fast moving things (kids playing, animals, aeroplanes, water...) it's the opposite, I'd need a faster shutter speed, to freeze the action so I'd want to choose the shutter speed. I'd prefer a sharp monkey and a blurry banana rather than a sharp tree and a blurry monkey.

Doing it manually does make you think more about these choices. When I shoot digital now I put it on P and spin the dial to get a combination that I'd like based on the rules of thumb above.

YMMV, good luck!
Alex
 
My MP is often used in a pseudo shutter priority mode, as it's easier to adjust the aperture than to constantly change the speed.
 
My first SLR, a Yashica TL Super, had a built in match-needle meter. As mentioned above, it was easier to change aperture than shutter speed. I didn't change the shutter as often as the aperture to move the needle. My next was the Fujica ST 901, with AP auto exposure. That I found much easier to use as the aperture and shutter speed could be viewed in the viewfinder. I could then very easily pick the combination I liked best.

One of the reasons I liked it most was for crime scene photography. On a tripod I could set the aperture for what I needed to include what I needed in the photo and let the camera pick the shutter up to 30 seconds. Much easier. It had dof preview to help me along.

I am surprised nobody has mentioned the Olympus OM1 where the shutter was just behind the lens mount. Shutter speed was no more difficult to select than the aperture according to users.
 
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