Aperture Priority mode not needed when using the Kit Lens?

Maybe it is my lack of knowledge of the photography trade, but I feel as if I do not need to use the aperture priority when using my kit 18-55 IS lens with my T2i. I feel as if I just cannot play a lot with the AV mode, since most of the time the aperture is set up to the lowest f-stop when shooting with the Auto/no flash mode anyways. I have read several book out there on photography, aperture, etc and it seems that until I get something like the 18-50 2.8 lens (at least), the aperture setting is would not be something I need to use.


I am mostly shooting kids and as a beginner, I am looking for that nice soft bukkah effect with their faces in focus. Only way I can do that with this lens is by going full wide at 55 and being few feet away from them.


Am I missing something here?

If you want a shallow depth of field (what you mislabel as "soft bukkah effect") then you really do need a larger aperture lens, something like a 50mm f/1.4.

As for using something other than a wide open aperture, there are situations where you would want to use f/8 or f/11 but portraiture with a shallow depth of field is not on that list.

That's is what Av is for. You set the aperture (wide open in your case so you can get a narrow DOF. In Av you set the aperture and it figures out the right shutter speed. Vice versa for Tv mode. You would then be concerned with shutter speed and let the camera pick the aperture. As you point out, the kit lens isn't very fast though and will usually land wide open. With either mode you can set your ISO speed or let the camera select that for you as well.

Get "Understanding Exposure" by Bryan Peterson. And welcome.

yes, shallow depth of field is what I meant.

I agree with you that 50 1.4 would create that and probably the 1.8 would be amazing and it is on my list to buy next, but I shoot a lot indoors and on my non-full frame body 50mm crops a lot.

If you think 50 is too long, you may want a Canon 28 f/1.8 or a Sigma 30 f/1.4 instead. The 50 f/1.8 is by far the cheapest trip into primes though. Think of it as a gateway drug.

Also consider the Sigma 30 f/1.4, just be aware that getting too close to the subject can add distortion that you may not want.

randy98mtu wrote in post #12665889
That's is what Av is for. You set the aperture (wide open in your case so you can get a narrow DOF. In Av you set the aperture and it figures out the right shutter speed. Vice versa for Tv mode. You would then be concerned with shutter speed and let the camera pick the aperture. As you point out, the kit lens isn't very fast though and will usually land wide open. With either mode you can set your ISO speed or let the camera select that for you as well.

Get "Understanding Exposure" by Bryan Peterson. And welcome.

Thanks for the recommendation. I have read a few on aperture and I understand the general concepts. Then I want to play around with my camera and get disappointed since I cannot play a lot with the aperture on the kit lens.

Now on the other hand, when I slap on the 50-250 lens, I get great bukeh effect (then it is bukeh right?) but as I said on my body, that lens crops so much and lot of times I do not carry it with me.

When doing portraits I like to set a fast shutter speed as high as 1/1000 when on the beach on a sunny day just so I can capture nice facial expressions.


I did get the 18-135 so I will play around with it a bit. Am I correct in the expectaiton that a bukkah effect would be more pronounced with this lens compared to the 18-55 lens?

Maybe I just need to sell both 18-55 and the 17-135 and get a 24-70 2.8 lens?

You still can set Av with kit lens provided you are shooting f4.5 and above.

To get the bokeh from kit lens, yes all the way to its longest focal length with the largest allowed aperture. The distance between the subject and its background play a factor to the bokeh effect as well.

The correct term is bokeh. Focal length comes into play, but it's mostly a factor of aperture. You will want a 2.8 zoom or a fast prime.

Look through your pictures exif data to see what focal lengths you use most. That will help you decide what prime to get. For crop you will probably want a 28/30mm, 50mm, or 85mm. With the exception of the 50 1.8, which is $120, the others are all around $400 give or take. For zooms, you can get a Tamron 17-50 f/2.8 for around $400, up to a Canon 17-55 f/2.8 IS for $1000, or the 24-70 for $1400ish?

As you noted, getting shallow dof/nice bokeh from a kit lens requires being close to the subject and using a longer focal length.

"Bokeh", not "bukkah"...

The longer the focal length of the lens, when used pretty close, the more you will be able to throw the background out of focus at any given aperture.

Use Av for serveral purposes... one being to control depth of field and background blur. Another is that most lenses have a "sweet spot" aperture or apertures, such as f5.6 to f8, where they are sharpest. Of course you will want to go the other way to a larger aperture such as f3.5 or bigger if your lens can do larger, to blur down the background.

A lot of experienced photographers use Av much of the time, since it leaves you in control of the depth of field and the "look of the image". You might switch to Tv, or Shutter Priority, if taking sports/action shots and wanting a fast enough shutter speed to stop movement.

Get the book "Understanding Exposure" by Bryan Peterson. It's a good read and will explain all this in much greater detail... everyone new to photography and SLR cameras should be required to read and study that book (along with their camera manual) before being allowed to post questions here

I actually find myself shooting AV mode a lot these days (had my T1i for ~2 years). I went from full auto to full manual and now to AV (mostly) over that time. Yes, your kit lens is limiting because it doesn't open very wide. So, you find yourself shooting nearly wide open all the time. But, if you get different lenses with more flexibility in your aperture choices, you may find AV a lot more useful.

These days (doing weekend stuff with the kids), I'll set my ISO at a level that, with a mid-range aperture (say f5 or f8), gives me good flexibility in shutter speed (1/250+) in the available light. Shooting something at 1/250 or 1/2000 doesn't matter a whole lot, unless I'm shooting action (which I usually don't), so I just pick an aperture that will give me a the DoF I'm looking for and let the camera auto adjust the SS. This saves me from needing to make two adjustments before shooting instead of just one, which improves my timing and the accuracy of the exposure.

Buy a 50mm f/1.8 and you may start to see a little more utility in the AV mode.

mplezia wrote in post #12666172
I actually find myself shooting AV mode a lot these days (had my T1i for ~2 years). I went from full auto to full manual and now to AV (mostly) over that time. Yes, your kit lens is limiting because it doesn't open very wide. So, you find yourself shooting nearly wide open all the time. But, if you get different lenses with more flexibility in your aperture choices, you may find AV a lot more useful.

These days (doing weekend stuff with the kids), I'll set my ISO at a level that, with a mid-range aperture (say f5 or f8), gives me good flexibility in shutter speed (1/250+) in the available light. Shooting something at 1/250 or 1/2000 doesn't matter a whole lot, unless I'm shooting action (which I usually don't), so I just pick an aperture that will give me a the DoF I'm looking for and let the camera auto adjust the SS. This saves me from needing to make two adjustments before shooting instead of just one, which improves my timing and the accuracy of the exposure.

Buy a 50mm f/1.8 and you may start to see a little more utility in the AV mode.

Thanks for your reply. I am not disputing the value of the AV mode, and I fully understand its importance. What you and most of you have said in this thread is that my assumption is correct. AV mode with the kit lens is fairly useless since the auto will most likely pick up the same shutter and aperture priorities that I would if I had shat at AV.

I may play with the lens to see if I can find the aperture "sweet spot".


Thanks!

randy98mtu wrote in post #12665912
If you think 50 is too long, you may want a Canon 28 f/1.8 or a Sigma 30 f/1.4 instead. The 50 f/1.8 is by far the cheapest trip into primes though. Think of it as a gateway drug.

I used to think primes were bull****......then I got a 50 1.8 and now I have like 9 Nikkor primes I use with an adapter.

Sure, if you are shooting only portraits. But there are a lot of subjects for which you want a large DOF, and AV is very useful with the kit lens. I understand that you are shooting mostly kids, and want to isolate them from their surroundings, so sure, you will usually be wide open if you are in low light and are not using a flash. But, if you want to get their surroundings, want to tell a story, want to shoot landscapes, close that baby down. What was the old saying for a great photo? f/8 and be there? There is more than just bokeh.

keano016 wrote in post #12666555
Thanks for your reply. I am not disputing the value of the AV mode, and I fully understand its importance. What you and most of you have said in this thread is that my assumption is correct. AV mode with the kit lens is fairly useless since the auto will most likely pick up the same shutter and aperture priorities that I would if I had shat at AV.

I may play with the lens to see if I can find the aperture "sweet spot".

Thanks!

One other thing I've grown into with Manual/AV mode is that I'm in control. Auto with the kit lens can produce nice pictures, but you give up the basic exposure control which I've really gotten used to in manual/AV mode.

A few other things about Auto mode with the kit lens that I don't like:
-- Auto focus points
-- Auto flash trigger
-- Auto ISO selection

Any one or two of those isn't a big deal. But, all auto is not for me. AV gives me control over the things I most want control over, but has a little added simplicity in setting the exposure, which I like.

There's certainly no "one right way" to take a picture though.