Aperture Priority Settings -- confused

[tatlyne]

I'm sure this will pan out to be a very silly question, but here goes. (New to DSLR) -- I was practising for depth of field. Picked my subject and selected various aperture settings. (using canon telephoto lens 75-300 mm). At f5.6 I expected a shallow depth of field - it wasn't. This was the best pic by far for sharpness of the whole scene which I would have expected from my next shot which I selected f/20. At f/20 however the shutter speed was 1/15 and the whole photo suffered from camera shake and was blurry. Both were taken with focal length 100 mm and ISO 800 (it was a shady area).

Question: When using aperture priority am I limited to using the shutter speed the camera chooses?

[kvbarkley]

You need to get a book about the exposure triangle. And google for a depth of field calculator.

First, the 75 - 300 is not a very good lens.

Second, f/5.6 is not a very small aperture. You would have to work hard to show dof effects.

Third, you can also vary the ISO to get a faster shutter speed.

You can use manual mode for direct control over all three components of exposure, but if you stray from the camera's suggestion your image will appear darker or lighter - which may or not be what you want. for example for sunsets you might want to make it darker.

To really see depth of field effects you need a lens lke the 50mm f/1.8, and keep the subject relatively close. (Note that the example in the manual uses some playing cards inches away from the lens.)

[Tronhard]

I would suggest doing some research into the exposure triangle.  Probably the best way to do so is via videos as you can see the points the tutors are making.

If you go to your local library website, do a search on their catalogue for Lynda.com - if the item appears open that link. It will take you to the website, which gives excellent video tutorials on a wide selection of topics, including photography.  The presenters are not only excellent photographes but good teachers and the production is top rate.   If your library has their website in their catalogue it means you have unlimited free access, (you log on using your library credentials) otherwise go to the website directly and you will get a free month's access without obligation.   Once there, do a search for photography foundations or the exposure settings - you should find several tutorials on the subject.  There is also a very rich list of topics from basic to advanced on technology, technique and terminology.

As an example, you might (you may have to join the site oruse the free month) be able to access this tutorial by Ben Long in his photography foundations series:

https://www.lynda.com/Digital-Photography-tutorials/foundations-of-photography-exposure/71923-2.html...

Failing that, do a search on Youtube for The Exposure Triangle and also for Aperture priority.  I think Canon even has some tutorials on this subject for their cameras.

I hope this helps

[tatlyne]

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@Tronhard wrote:

I would suggest doing some research into the exposure triangle.  Probably the best way to do so is via videos as you can see the points the tutors are making.

If you go to your local library website, do a search on their catalogue for Lynda.com - if the item appears open that link. It will take you to the website, which gives excellent video tutorials on a wide selection of topics, including photography.  The presenters are not only excellent photographes but good teachers and the production is top rate.   If your library has their website in their catalogue it means you have unlimited free access, (you log on using your library credentials) otherwise go to the website directly and you will get a free month's access without obligation.   Once there, do a search for photography foundations or the exposure settings - you should find several tutorials on the subject.  There is also a very rich list of topics from basic to advanced on technology, technique and terminology.

As an example, you might (you may have to join the site oruse the free month) be able to access this tutorial by Ben Long in his photography foundations series:

https://www.lynda.com/Digital-Photography-tutorials/foundations-of-photography-exposure/71923-2.html...

Failing that, do a search on Youtube for The Exposure Triangle and also for Aperture priority.  I think Canon even has some tutorials on this subject for their cameras.

I hope this helps

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Thank-you. I have been reading and watching videos. I will make a point to go to Lynda.com

[Waddizzle]

Here is a link to a recent thread that you might find useful.

https://community.usa.canon.com/t5/General-Camera-Discussion/Canon-YouTube-Video-Series/td-p/269237

[ebiggs1 · Accepted solution]

It is good to understand exposure but I don'tthink that is your question. And not the correct answer to your query. In favor of, or along with, checking out the exposure triangle you might want to get a DOF guide.

"At f5.6 I expected a shallow depth of field - it wasn't." "...the best pic by far for sharpness of the whole scene..."

This isn't an exposure thing.  It is a DOF thing.  Keep in mind besides the lens and the FL you select, DOF is effected by distance.  The closer or farther away you are from the main most important subject will change the scene.

"Question: When using aperture priority am I limited to using the shutter speed the camera chooses?"

Simple answer, yes. That is the idea of Av mode.  You fix the aperture and let the camera automatically select the SS for proper exposure. The SS does not effect DOF but it can cause blur!