CO777-200ER
Topic Author
Posts: 362
Joined: Mon Apr 30, 2001 6:57 am

Aperture

Fri Dec 21, 2001 3:36 am

Hello I am wondering how does Aperture affect your pictures that you take. On my camera I always have it set on F5.6. I am wondering if on certain days I should change it if it is cloudy or sunny.

JOEY
 
AndyEastMids
Posts: 1055
Joined: Wed Jan 24, 2001 10:24 pm

RE: Aperture

Fri Dec 21, 2001 3:57 am

Simplistically, the only reason why you should change your apperture on cloudy or sunny days is because the apperture set effects the shutter speed the camera chooses. For any given level of light, smaller apperture equals slower shutter speed, wider apperture equals higher shutter speed. So, on dull days, you might find that F5.6 gives an unacceptably slow shutter speed and you might want to increase the apperture (set a lower number) whilst on bright days... Well on bright days you might want set a smaller apperture to get more depth of field (depth of field, what's that?).


So, aside from the relationship between appertue and shutter speed, the main effect of apperture is on depth of field. Depth of field is the area (distance) in front of and behind the focus point, which will also appear to be sharp. The smaller the apperture (a small aperture is a big number - i.e. F11 is smaller than F5.6), the greater the depth of field, and vice versa.

In aviation photography, when taking a side on picture of an airplane, depth of field has relatively little impact on the result as essentially the majority of the airplane is at the same distance from the camera. So assuming you can focus correctly, the majority of the airplane should be in focus anyway. However, if you were to shoot a relative close up from the nose of an airplane, depth of field becomes more important because with a small/narrow depth of field the nose might be in focus whilst the tail isn't. Bottom line is that if you want a picture to be sharp across a wide distance, you need to select a smaller apperture.


However, the is one further consideration regarding apperture, and that is that all lenses perform better and give sharper results at smaller appertures (remember small apperture means big number) than they do at large appertures. Particularly, most lenses won't give overly sharp results at their largest apperture. It thus makes sense to try to use an apperture part way up the scale if possible, and try to avoid the maximum. In this respect, F5.6 should not be a problem (unless F5.6 is the maximum apperture of your lens), but F8.0 might give better sharper results. However, given the relationship between apperture and shutter speed, you may sometimes be forced to use a larger apperture than is ideal, just to keep the shutter speed up to an acceptable level.

Clear??? As mud!  Nuts Thought so.  Big grin Oh well...

Andy
 
G-CIVP
Posts: 1408
Joined: Tue Mar 20, 2001 6:38 am

RE: Aperture

Fri Dec 21, 2001 4:43 am

Pretty clear to me. To use a practical example, using 100 film on a bright sunny day, taking landing shots at LHR, using a good camera and good zoom lens, what would be the best aperture and speed setting in general terms?

I'm not trying to trick anyone here, I just want to confirm my own settings are in the right direction!!
 
KingWide
Posts: 698
Joined: Thu Aug 02, 2001 7:30 am

RE: Aperture

Fri Dec 21, 2001 4:48 am

I'm normally on about 1/1000 @ f8 on 200 ASA so probably about 1/500 @ f8 would be ideal on 100 ASA.


J
Jason Taperell - AirTeamImages
 
DSMav8r
Posts: 575
Joined: Wed Mar 01, 2000 2:32 pm

RE: Aperture

Fri Dec 21, 2001 5:17 am

Generally speaking, the sharpest apertures are f8 and f11, but that is not always true.

As a rule of thumb, your lens' sharpest aperture is usually two stops down from the maximum aperture...So, if your lens' maximum is f5.6, your lens will be sharpest at f11, if f4, your sharpest would be f8, etc, etc...

If you have aperture priority mode, just set your camera to the sharpest aperture for your particular lens, then let the camera determine the shutter speed.


Aric Thalman
Omaha, USA
To most people, the sky is the limit. To those who love aviation, the sky is home
 
Staffan
Posts: 3879
Joined: Tue Mar 18, 2008 9:21 am

RE: Aperture

Fri Dec 21, 2001 9:01 am

I was going to start a new thread, but I might as well ask it here. Can anyone explain how come the aperture changes the depth of field? Does anyone know a webpage that sketches it up?
Also, I've seen that certain cameras feature DOF preview, how does that work?

Thanks,

Staffan  Confused
 
rindt
Posts: 876
Joined: Thu May 25, 2000 3:08 pm

RE: Aperture

Fri Dec 21, 2001 3:46 pm

Aric,

So you're saying F5.6 is the sweet-spot on an F2.8 piece of glass??? I only use F8, and sometimes F5.6 if I need a higher shutter speed to "freeze" the background (like I did today for JMC A330... what a beauty, but that's another story all together). For ramp shots, it's gotta be F8 or F11... nothing wider.

-Rob

What other people think of you is none of your business!
 
AndyEastMids
Posts: 1055
Joined: Wed Jan 24, 2001 10:24 pm

RE: Aperture

Fri Dec 21, 2001 10:07 pm

 
DSMav8r
Posts: 575
Joined: Wed Mar 01, 2000 2:32 pm

RE: Aperture

Sat Dec 22, 2001 2:32 am

Rob,

Technically yes, most constant 2.8 lenses are sharpest at f5.6, but the falloff will not be that significant until you reach f16, which is still barely evident unless you blow up your photos past 11x14.

It really can depend on the lens sometimes though...For example, my Tokina 28-70mm 2.8 is sharpest @ f5.6, whereas my Nikkor 80-200mm 2.8 is sharpest @ f8. But, there are just some situations where f5.6 is just way too wide, especially during bright sunny days...

Aric Thalman
Omaha, NE
To most people, the sky is the limit. To those who love aviation, the sky is home
 
CO777-200ER
Topic Author
Posts: 362
Joined: Mon Apr 30, 2001 6:57 am

RE: Aperture

Sat Dec 22, 2001 3:22 am

Thanks everyone for the replies. The lens I use is a Nikon 75-300mm. I always have my shutter speed at 1/2000 so saying that I better but my aperture at F8. The maximum for my camera is F4.2 or something like that. I mainly take arrival and departure shots.
 
Staffan
Posts: 3879
Joined: Tue Mar 18, 2008 9:21 am

RE: Aperture

Sat Dec 22, 2001 3:27 am

Andy, Thanks, that was what I was looking for!

Regards,

Staffan
 
CO777-200ER
Topic Author
Posts: 362
Joined: Mon Apr 30, 2001 6:57 am

RE: Aperture

Sat Dec 22, 2001 3:54 am

I was checking my camera and the minumum aperture it goes to is F32 and the maximum is F4.8, so I am wondering what aperture should I put it on.

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