Digital cameras 101

[Mickey]

Hi!  This might be a stupid question but I want to ask it anyway as I wanted to really understand it.

What is the "real" purpose of a camera's aperture setting?  Is it only for "effect" to control the DOF or is it used to control proper exposure of the picture?

What are the advantages of using a wider aperture opening for different types of subject like landscapes or portraits or macros?  Generally speaking, are lenses with wider aperture openings really better than those that have smaller openings?  

[ShutterbugGail]

Hi Mikey,

Welcome to the Q&A Board.

It's not a stupid question at all. The aperture, in combination with the shutter speed, is used to obtain proper exposure. The wider the aperture, the more light comes into the camera lens.

It is very important for controlling depth of field. I think these sections at our main website will give you the info you're looking for. If not, come on back.  

Aperture:
http://www.digicamhelp.com/advanced-digital-camera-settings/aperture.htm

Controlling depth of field:
http://www.digicamhelp.com/taking-pictures/depth-of-field.htm

Related reading: Shutter speed

http://www.digicamhelp.com/advanced-digital-camera-settings/shutter-speed.htm

[Mikey]

Thanks for quick response!!  The reference you gave are really helpful but I guess it brings up some more questions in my mind...

Is the aperture setting related to the distance of the subject from the camera's lens?  What would be the difference if I take a portrait shot (head shot) of person using f1.8 and f11 under the same shooting conditions?  Would some parts of the suject's face become blurred in the f1.8 setting?  

On the other hand, if I'm taking a landscape shot.  Should I use the widest or smallest aperture setting possible?  What would be the difference if say I used an f8 or f16 in this shot?

[Deb]

Hi Mickey, yes aperture is also related to the distance you are from your subject. At the same fixed aperture (say, F5.6), the closer you are to your subject (or zoomed in to your subject) the shorter the depth-of-field will be. Conversely, if your distance to the subject remains the same, the larger the aperture (smaller the F number), the shorter your depth-of-focus will be.

If you shot a portrait with an F1.8 then another at F11 (distance to subject being constant), you would notice features both in front of the focussing point and behind the focussing point begin to soften (go out of focus). That is, your depth-of-focus would increase with the F11 selection.

If you are shooting landscapes, aperture selection would be a way to include or exclude foreground or background elements. If you wanted everything to be in focus, you'd use a very tiny aperture (F22 for example). If you wanted an element in the foreground to be in focus (say a cool rock or flower) and you wanted to emphasis that element, you'd select a large aperture (say F5.6) and focus on that rock/flower. The background would then be out-of-focus.

If you want to really get a handle on aperture settings/distance and their effects, I'd run a bunch a shots of a fence row or something similar. (My dad taught me this exercise.) Find a fence row and stand with it at an angle from your position. In other words, not parallel to you or perpendicular to you. For the first run, keep your distance from the fence row constant as well as your focussing point, then take consecutive shots with different apertures selected. Do this in aperture priority mode so that your exposures will be accurate. For the second series, keep your aperture constant and alter the distance from which you are shooting. Keep the focussing point the same. This is a great way to see what aperture/distance changes do and a great way to learn. It's even fun!  

Hope this helps.  

[ShutterbugGail]

Deb is right. Go out and take some test photos using some of the principles that have been shared with you.

Here are some helpful illustrations. You probably don't want to read all the stuff, but the series of photos in each are excellent illustrations of depth of field at varying apertures:

http://en.wikipedia.org/wiki/Depth_of_field

http://www.deluxacademy.com/articles/digitalphoto/depth.html

[Mickey]

thanks so much for the inputs!!!  i've really learned a lot from these materials!!  i now have to practice and hopefully learn how i can control the DOP of ky camera and lens!!  

[Deb]

Have a great time!  

[alanek]

Hi
I am using a Canon IXUS 500, but cannot find how to change the Aperture.

I have found settngs for ISO (50 to 400), and Exposure (-2 to +2).

I am trying to take portrait photos where the background is blurred, but have not found how to achieve finding a way to modify the Aperture setting.
Any ideas?

[ShutterbugGail]

Hi alanek,

Welcome to the Q&A Board!

You can not manually change the aperture on the IXUS 500, also known as the PowerShot S500. This ultra compact model doesn't have a portrait scene mode either. Fortunately, there are things you can do to get the background blurred, known as shallow (less) depth of field. With a few setting changes and practice, you should get some great portait shots.

Generally speaking, the longer focal lengths (zooming in) produce less depth of field (out of focus, blurred background) something desireable when taking a portrait shot. With a digital camera, you can make the background appear out of focus by placing the subject close to the camera and having the background far away (but not too far).

Camera settings:

Use the dial to put your camera in Manual mode (the icon is a camera with an M next to it).

Change the iso to IS0 50. Since lower ISO means more light is needed to take the shot, a wider aperture (larger opening) will automatically be selected by the camera. The wider the aperture the less depth of field
there will be. Make sure you're taking the photo in adequate light to prevent camera shake (or use a tripod). If you have no other choice, use ISO 100.

To get more accurate focus, I suggest you turn AiAF 9 point automatic autofocus off for this type of close-up shot. You'll then be using a Single Center focus mode and you can control exactly where you want the camera to focus (I suggest the eyes or somewhere else on the face).

Taking the picture:

Zoom your camera all the way (3x), then pull back ever so slightly. This will help prevent barrel distortion known as pin cushioning, which can happen at full tele.

Stand as close to the subject as possible while still being able to achieve a focus lock.

Take some practice shots to see some of the effects you get. Let us know how it goes and, of course, if you have further questions, don't hesitate to ask.

Related reading:

Apeture
http://www.digicamhelp.com/advanced-digital-camera-settings/aperture.htm

Depth of field:
http://www.digicamhelp.com/taking-pictures/depth-of-field.htm

[GoGayleGo]

Good morning and Happy Holidays,

I'm new here.  I've owned a Kodak DX6340 for a couple of years, and bought it specifically for the manual controls (which I had/have no idea how to use BTW, but figured I'd learn!).

I have recently become obsessed with trying to take photos where the subject is in focus, but the background is not (I have been wildly unsuccessful with this undertaking so far).  I understand that this has to do with DOF and aperture control.

Read through the boards this morning, then took a couple of test photos, but I do not have good news to report.  I tried using both the "portrait" mode (and zoomed in with the telephoto lens) as well as the Aperture priority mode (several f-stops, starting with the smallest number which I believe was 4., while I remained in the same place.  All of these photos looked the same, both on the LCD before snapping, as well as after the fact, upon reviewing (and every single one of them had the full field in focus...aaaaaagh!).

I'm wondering if there's some basic setting on this camera that is overriding what I'm trying to do, or if there is some other very basic "thing" that I'm not doing in order to get this to work.  It doesn't seem like it should be this hard!

I e-mailed Kodak for help, and twice now they've answered questions tangential to the one I'm asking, but not what I need to know.  I'm feeling quite desperate and hoping someone out here can steer me in the right direction!

Thanks in advance for your time and help.
Gayle

[Deb]

Hi there GoGayleGo and welcome to the Board!

To get the shallow depth-of-field like you described in your post you need to be focused on an object/subject near you. (Other techniques are possible too but let's stick with this more basic one to start with.) If you are using a wide open aperture (f4 was the one you mentioned), but are focussing on a midrange or distant object, you may not get the results you are seeking. Do you remember about how far away from your subject you were when you took your shots? Were you focussed on a near subject? Perhaps you can give us a link to a url where you can upload your images for us to review.   BTW, offhand, I'm not aware of settings on your camera which would override your mode selections but I'd need to browse the manual to be sure.

[GoGayleGo]

Hi Deb,

Thanks for the quick reply.

Subject (aka husband) was only several feet from me.  I even moved from indoors to out, to ensure that there was sufficient depth behind him when we took the pictures.  In some cases, I was the subject (when I had my husband trade places and give it a try).

Well, I'll have to take some different pictures to post, as we were both making crazy faces in these shots!  It may take a day or so, since it looks like it may rain here at any moment, and I really wanted to do this outdoors where there's lots of space.

Stay tuned, and I'll take any other advice/suggestions that you may have!

Gayle

[Deb]

Subject (aka husband) was only several feet from me.

Hmmmmm, that's odd that you didn't get the desired effect. Being focused on a subject that near should have done the trick with an aperture of f4. I'll pull up an online manual for your camera model and see if I can find anything that might explain this issue. In the meantime, I'll await your new photos. But you don't need to be bashful. We love to see people shots with crazy expressions! So if you want to upload 'em, we'll enjoy viewing them.

[Deb]

Hi, just want to double-check something .... You are following the steps found here http://www.kodak.com/global/en/service/publications/urg00132toc.jhtml?chapsec=urg00132c2s3&pq-path=10/3905/3921/972/1605#CCHIJEIE for setting your aperture, yes?

[GoGayleGo]

Yes, those are exactly the steps I'm following.  I have no trouble getting to the proper screen, or toggling over to adjust the setting (and actually making the adjustment), I just don't seem to be seeing any effects when I do so.  Having not tried it before, I have no way of knowing if there is truly something "wrong" with the camera, or if it's just user error!

[ShutterbugGail]

Try using even a larger aperture if your camera has it, such as f 2.8. Also, if possible, move the subject a bit further away from the background. In conjunction with both of these, zoom in closer.

If you haven't already done so, check out the section on Shallow Depth of Field.

http://www.digicamhelp.com/what-is-depth-of-field/index.htm

Darn, you're not going to show us those crazy faces?  

[GoGayleGo]

Try using even a larger aperture if your camera has it, such as f 2.8. Also, if possible, move the subject a bit further away from the background. In conjunction with both of these, zoom in closer.

If you haven't already done so, check out the section on Shallow Depth of Field.

http://www.digicamhelp.com/what-is-depth-of-field/index.htm

Darn, you're not going to show us those crazy faces?  

[GoGayleGo]

OK, let's try this again, hopefully with better results!

Darn, you're not going to show us those crazy faces?  

I've actually deleted the photos, so even blackmail can't get me to give them up!  

I haven't had time to get out to try some more pictures yet - I've been off of work all week and have spent nearly every free moment hiking.

But all that hiking time gave me time to think about this, and I'm wondering something: If I'm using aperture priority mode, where I set the aperture, but the CAMERA sets the shutter speed, will it pick one that will cause the whole scene to be in focus?  Essentially undoing what I'm trying to do?  Do I really need to be in full manual/program mode, where I pick both the aperture AND the shutter speed to achieve the effect I'm looking for?

Happy New Year!

[ShutterbugGail]

I've actually deleted the photos, so even blackmail can't get me to give them up!

Hee, hee.

If I'm using aperture priority mode, where I set the aperture, but the CAMERA sets the shutter speed, will it pick one that will cause the whole scene to be in focus?

If by focus, you mean depth of field, the shutter speed has no effect on it. It's the aperture you must watch (and, of course, locking focus where you want it).

Do I really need to be in full manual/program mode, where I pick both the aperture AND the shutter speed to achieve the effect I'm looking for?

In my opinion, you do not need to be in full manual mode. Aperture Priority mode is just fine.

Let us know how it goes.

[GoGayleGo]

It didn't go well.  I took 17 photos overall.  None with an aperture greater than 2.8, and most at 2.2.  (None with the telephoto lens, as I can't get that small of an aperture when using it).  All of my husband, none with him more than 5 feet from the camera.

Where/how do you suggest I post these for you to look at?  PLEASE don't laugh - it's an overcast day and you will see that there are exposure issues going on here - I did experiment with autoflash, no flash, and fill-in.  I finally moved him to a darker area to try to diminish the glare.  The angle isn't so good either.

Anyway, the point was to see if I could get a blurry background, and in spite of all the other technical difficulties, I think you will clearly see that this goal was not achieved.