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Old Apr 3, 2010, 5:14 AM   #1
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Default High aperture and slow shutter speed, poor results.

In the book Im reading, the author suggests using a higher aperture such as f/11 - f/22. He said you would ge better overall sharpness with such a setting with a low ISO. So in the following pic, I set the aperture to f/16 and shutter speed to 30 seconds with an ISO of 100. This setting was not what the light meter recommended, but instead a bit darker given the environment. With such settings, I kinda expected a darker and clearer picture, but what I got was a bright unsharp picture. Oh this was also taken on a tripod with a 10 second delay to aboide shake, IS was off. Since I cant ask the author, I thought Id ask here.

Here is the full res
http://i.imgur.com/Tcxgh.jpg


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Old Apr 3, 2010, 6:54 AM   #2
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Don't believe everything you read..... hmmm, OK, so you might not believe this LOL.

It will depend on how they are defining sharpness. With a narrow aperture like the f11-22 range you do get more depth of field so more of the photo is in focus (this could be what they are defining as overall sharpness), but actually at over f11 on an APC-C digital camera (anything with a 1.5 or 1.6x crop factor) then results are getting softer.

This article will explain more. http://www.bobatkins.com/photography...ffraction.html

With the metering, it is the same situation as a couple of days ago. You are trying to meter for a very dark situation. The camera will naturally try to make the dark exposed 'normally' which is much brighter than you would want to see it, and then the light areas are even far more bright than desired. It will try to get the best compromise, but it is just guessing so rarely gets it right. This is why for night photography you want to be shooting manual settings to get the desired results or spot meter on an element that needs to be exposed correctly.

The shooting at a low ISO is the correct advice for minimum noise, but then you need to ensure you get a shutter speed that works for your situation.... so when hand holding then often you need a faster shutter speed so you might want to increase the ISO. For tripod shots then you can wait longer without the fear of movement so it's not an issue.

I would personally start with shooting more simple shots, where lighting is balanced, with your recent examples you are really working in areas where the learning curve is vast, as not only are you trying to work out a new camera but also trying to capture shots that are very very hard to make look good.

If you want to practise in the evenings then I would say go for indoors, still use the tripod etc and play around, but at least lighting is more balanced in a room.... yes there will be hot spots but you probably won't get so frustrated.

I would look into the metering modes of the camera so you understand what it is trying to do in each one and when to use them. I use evaluative 95% of the time then the rest is spot metering for something specific.

One interesting test to do is to photograph two blank walls (or pretty blank), one that is very dark and one that is very light Don't let the camera see anything different in the photo so it is only wall. You will find that even though we see one as dark and one as light, the camera doesn't and will expose them to be the same.

Just to show what I mean, I found where I can do a comparison of light and dark which is the black piano against a light cream/brown wall. The first shot is a normal evaluative metered shot of the scene which is pretty much what we would expect the camera to produce. Yes the white balance isn't spot on, but I wasn't going to worry about doing a custom one for this quick sample.

The next one is the wall just left of the embroidery and the last is the piano which you can see the reflection of the camera and some other light areas. If this wasn't reflective the test would have been better as it would have been more uniform, so as it is there are some areas which are lighter than the wall exposure and some darker, overall though both photos have the same average exposure. I have no walls that are dark so couldn't quite do what I was suggesting. Even so, as you can see the camera has made the wall a lot darker than it really is, as it has no way of knowing it is light. With the piano, it is a lot lighter than we would see it as the camera doesn't know it is black. So this is the same issue you will have with photographing dark scenes, or light scenes for that matter.

Hope that helps a bit more.

Lastly, the dark corners of the photos are due to the lens I was using.
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Old Apr 3, 2010, 7:15 AM   #3
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Night time shooting is really an experimental thing so try a selection of settings until you get the effect you wanted. Because of the extreme dynamic range you are unlikely to get everything properly exposed.

The lack of sharpness may be due to diffraction, see http://www.cambridgeincolour.com/tut...hotography.htm for an explanation.
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Old Apr 3, 2010, 1:39 PM   #4
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Another thing to consider as far as sharpness of long exposure shots is concerned, particularly at night, is atmospheric haze and dust. As the temperature falls with darkness, the moisture in the air begins to condense out into fog. Even when not visible to the eye, it can be a factor for long exposures.

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Old Apr 3, 2010, 7:28 PM   #5
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Quote:
Originally Posted by Mark1616 View Post
Don't believe everything you read..... hmmm, OK, so you might not believe this LOL.

It will depend on how they are defining sharpness. With a narrow aperture like the f11-22 range you do get more depth of field so more of the photo is in focus (this could be what they are defining as overall sharpness), but actually at over f11 on an APC-C digital camera (anything with a 1.5 or 1.6x crop factor) then results are getting softer.

This article will explain more. http://www.bobatkins.com/photography...ffraction.html
I have only has time to absorb this part of your post, as its very informative. Though from what you said and the link posted, for clarity I should try to stick with a smaller aperture like f/11 or f/16. So my question is, if I can only go as small as f/16, and my camera DSLR only has a max shutter speed of 30 seconds, am I then forced to move up from ISO 100? I have seen some pretty amazing night shots, some with the same camera, so I am a bit confused if its the lens? Do certain lenses enable the sensor to work better at smaller apertures?

Thanks again.
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Old Apr 3, 2010, 7:37 PM   #6
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You don't need to go crazy small to get good sharpness and enough depth of field. Personally I would look at f8 or f11 maximum. Check out http://www.dofmaster.com/dofjs.html which will allow you to see with different settings how much will be in focus in front and behind the focal point.

As for different lenses giving differing results.... some will be sharper, but f8 on one lens will give the same light as f8 on another.

If you have some photos you've seen that you would like to recreate, then it is worth posting a link to them then we can try to advise. Please don't copy and post the photo itself as it is likely to be copyright.

You should be able to get great results with the kit you have so keep at it.
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Old Apr 3, 2010, 7:38 PM   #7
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Heavybird,

Which shooting style are you selecting on your T1i?

PS

Also depending on the lens, you may get better sharpness with one vs another lens. I do notice that my fast prime are better in sharpness then my zoom stop down when doing night shots.
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Last edited by shoturtle; Apr 3, 2010 at 7:51 PM.
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Old Apr 3, 2010, 9:46 PM   #8
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Quote:
Originally Posted by shoturtle View Post
Heavybird,

Which shooting style are you selecting on your T1i?

PS

Also depending on the lens, you may get better sharpness with one vs another lens. I do notice that my fast prime are better in sharpness then my zoom stop down when doing night shots.
Not really sure on what you mean by shooting style. I mainly shoot in mode M with picture style S (Standard). I tend to use AWB and Evaluative metering.
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Old Apr 3, 2010, 10:27 PM   #9
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in the shooting style of standard. You have user define ones. You can up the sharpness of the photo, the contrast, color tone, saturation. You can choose to increase any of these setting.

So if you are not have at with the sharpness at standard, which is set at 3, you can choose landscape which is set at 4. Of you can use one of the user define and set the sharpness to the max of 7 if you prefer. It actually helps out.
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Old Apr 3, 2010, 10:40 PM   #10
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Here are 2 example where I played around with the style settings

first one was sharpness at 4, contrast, saturation and color tone all +1
second was sharpness at 7, contrast and saturation at +3 and color tone at +2
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