Large Aperture vs small aperture (Page 2): Hello, Dumb question here from a novice. I understand the way aperture works but not sure I understand the practical need for large...

paulrph1 Loc: Washington, Utah

[quote=rthompson10]Hello,

Dumb question here from a novice. I understand the way aperture works but not sure I understand the practical need for large apertures. If I get a lens capable of 1.4 or 1.2 yes that's great for low light but my DOF is so small that I'm not sure how practical if shooting people for example

One thing a person learns in life is there are limitation to everything we deal with. Learning to cope and alter those limitation is in reality a great thing. Many have done much and continue to do so to use these to their advantage. It really is a beautiful thing.

zigipha Loc: north nj

lamiaceae wrote:

1) So you can easily (manually) focus.
2) Low light when you are focused near or at infinity you only need shallow DOF. Say night scenics or astro-photography. Also wide angle lenses have huge inherent DOF and so don't really need to be stopped down much or at all.

Not really; focal length has very little to do with DoF

paulrph1 Loc: Washington, Utah

[quote=rthompson10]Hello,

Dumb question here from a novice. I understand the way aperture works but not sure I understand the practical need for large apertures. If I get a lens capable of 1.4 or 1.2 yes that's great for low light but my DOF is so small that I'm not sure how practical if shooting people for example- Am I missing something?

There are things man has invented to help with all of this. Tripods, cable releases, subjects that do not move and many many more. The big problem is carrying everything around. Sherpa anyone?

ole sarg Loc: south florida

size of sensor effects DOF too.

see: http://www.lightstalking.com/cameras-sensor-size/

davidrb Loc: Half way there on the 45th Parallel

rthompson10 wrote:

Hello,

Dumb question here from a novice. I understand the way aperture works but not sure I understand the practical need for large apertures. If I get a lens capable of 1.4 or 1.2 yes that's great for low light but my DOF is so small that I'm not sure how practical if shooting people for example- Am I missing something?

Thanks
RT

What is missing from this thread is the fact that the AF system (Canon) works in different manners with different aperture lenses. Lenses that are f/2.8 or faster will auto-focus much quicker than the higher aperture lenses. There are different type focus points that are used in separate areas of the focus pattern. Dual cross types are the most desirable, and the fewest of all points. These are the points that are designed to work with the larger apertured lenses. As an example, the Canon 24-105 will take longer to AF with it's f/4.0 aperture while the 24mm with an f/1.4 aperture will be much faster as it is using all cross-type focus points.

Marionsho Loc: Kansas

zigipha wrote:

Not really; focal length has very little to do with DoF

Yeah right. What a misleading reply. :thumbdown:

ralphc4176 Loc: Conyers, GA

Most of my lenses are fast (f/2 or faster prime lenses, f/2.8 zoom lenses). The fast lenses can get shots that other lenses cannot feasibly get (without increasing the camera ISO, which can lead to grainier images). And, of course, you can always close down a fast lens to f/16 (or smaller) for a shot with greater depth of field when you have enough light. There's the issue--how much light do you have? If you don't have much, there are some shots you cannot feasibly get with a slower lens. But you may never need to go to the extra expense of a fast lens--depends on your needs.

rmalarz Loc: Tempe, Arizona

zigipha wrote:

Not really; focal length has very little to do with DoF

Focal length has a lot to do with DOF.

Read the section titled, "Is it true that longer lenses produce a shallower depth of field?"

http://www.digitalcameraworld.com/2013/07/17/what-is-depth-of-field-how-aperture-focal-length-and-focus-control-whats-sharp/
--Bob

James R. Kyle Loc: Saint Louis, Missouri (A Suburb of Ferguson)

OldEarl wrote:

I agree with Gene. There are pictures which rely on shallow depth of field--and aperture is one of the factors that the photographer can control. By using a fast shutter speed, I can open up and skip a lot of the background. I also like to shoot in the lower ISO range which improves quality in film and possibly also in digital.

++++++++++++++++++++++

I too agree with Gene... (He is always correct with ALL of his help to others here)...

The use of DOF in ANY photographic print (or digital posted image) is the way to draw the attention of others to "LOOK HERE" == SEE THIS.... and THIS IS OF IMPORTANCE.

And it is true that Most of my landscape prints are all TOTALLY in focus. However... With people, and macro-photography, as well as some "tight-in" shots were I wish to give "special" attention to a particular item in the frame = I shall use a 2.8 rather that 16 on the Aperture of any lens that I have which will "go the distance" for what I deem Important.

It is all in what You the photographer wishes to show to others.

To me = That is what Depth of Field is about.

gemlenz Loc: Gilbert Arizona

Gene51 wrote:

Shallow depth of field is used creatively to de-em... (show quote)

:thumbup: :thumbup:

Math78 Loc: Scottsdale, AZ

Gene51 wrote:

Shallow depth of field is used creatively to de-emphasize distracting backround and/or foreground elements using out of focus blurring, isolating the principal element with crisp focus.

Love the starling! What a great DOF example to share.

Weddingguy Loc: British Columbia - Canada

bkyser wrote:

Also, a larger aperture helps with focusing. Your... (show quote)

:thumbup: This is why most event photographers that are forced to shoot in low light situations use fast lenses with constant apertures throughout the zoom range. Event photography rarely requires the shallow DOF of the faster lens, but focusing in low light situations can be a challenge.

Architect1776 Loc: In my mind

rthompson10 wrote:

Hello,

Dumb question here from a novice. I understand the way aperture works but not sure I understand the practical need for large apertures. If I get a lens capable of 1.4 or 1.2 yes that's great for low light but my DOF is so small that I'm not sure how practical if shooting people for example- Am I missing something?

Thanks
RT

I started out with a 50mm f1.4 lens on a FTb several centuries ago. Never found it to be a problem when taking photos of people in low light and having DOF an issue. Guess I stood back far enough.
There are compromises with everything photographic. Large aperture shallow DOF but faster shutter speed available. Smaller aperture more DOF and slower shutter unless you change ISO then you get noise with high ISO and what is your tolerance for that.
Perhaps experimenting a bit and see what you like and find acceptable in your opinion would be a good place to start.

jimmya Loc: Phoenix

rthompson10 wrote:

Hello,

Dumb question here from a novice. I understand the way aperture works but not sure I understand the practical need for large apertures. If I get a lens capable of 1.4 or 1.2 yes that's great for low light but my DOF is so small that I'm not sure how practical if shooting people for example- Am I missing something?

Thanks
RT

No you're missing nothing. I've shot indoor portraits under in home window light with my 50mm f/1.8. I normally focus on my subjects eye. In this case I've had the tip of the nose and an ear out of focus.

It depends on what you want. For my subject and me these shots were fine but if you're of a different thought then you need to add light somehow - flash, closer to the window, something to get more light on your subject.

wilsondl2 Loc: Lincoln, Nebraska

zigipha wrote:

Not really; focal length has very little to do with DoF

You should add to this "from the same shooting distance. This is shown by taking a picture with a telephoto lens and then a wide angle lens. Then you blow up the wide angle until you get the same size image you have with the telephoto and bingo they have the same depth of field. So in practice you use a longer lens for shallow depth of field and a wide angle for more depth of field. You have to move the camera to get the framing you want. - Dave