Camera Labs

Newbie question.

I'm confused about something in one of the video tutorials (which are FAB by the way ) - in the video "DSLR Tips: Night Photography", the recommendation is to open the aperture right up (i.e. the lowest possible f-value) to allow as much light into the camera as possibly. But wouldn't this create a really shallow depth of field and then a lot of the scenery would be out of focus?

Or does the extra long shutter opening somehow stop this from happening?

Thanks very much in advance for your help!

Well opening the aperture will have this effect, yes.

If you are shooting with no tripod, then opening the aperture and upping the ISO can give you the required shutter speed to get the shot you require.

For example, if the metering reckons you need 1 second at F8, ISO200, then if you double the ISO 3 times (through 400, 800 to 1600) you will require three times less shutter speed to capture the same amount of light. Therefore your shutter speed will go from 1 second to 3 stops faster (through 1/2 second, 1/4 second to 1/8th sec).

Then if you stop down from F8 to F5.6, to F4, to F2.8 you will gain another three stops of shutter speed. You shutter speed can then climb from 1/8th, through 1/15th, 1/30th to 1/60th second.

Now if everything in the shot is reasonably far from the lens and there is no foreground interest you got a keeper handheld at 1/60th, f2.8, ISO1600 which would not be possible at 1 second, f8, ISO200. However if you've got foreground interest you will have a shallow depth of field which may not give you the effect you're after.

This is where a tripod comes in.

Here's a hand held example:



This was at 1/80th second at f1.4. To get near the reciprocal of the focal length (85mm lens = 1/80th second shutter speed to try to get a sharp shot) I had to bump the ISO up to 2800. As everything is near infinity the aperture isn't a concern. In fact, because I didn't use a tripod the shutter speed had to be relatively fast, which give nice ripples on the water's surface rather than the blurry effect you'd get with a long shutter.

If you're shooting architecture, nightscapes etc I would definitely recommend a couple of things.

1. A good tripod
2. Using a remote shutter release, or camera's built in timer (to avoid moving the camera during the shot)
3. Mirror up if available
4. Bracketing your shots. You will have a very high dynamic range scene in front of you, with dark shadows and highlights from, er, lights! Bracketing and then merging in photoshop (or using HDR software) can blend the shots to a view more like the one you saw with your eyes.
5. If taking single exposures rather than bracketing, then at least checking your histogram to see that you're not blowing highlights too much (there will always be some blown highlights when dealing with street lights and architectural lights), and adjusting your shutter speed to suit.
6. Lens hood (to avoid or minimise flare from street lights out of shot but casting light on the lens)
7. Shoot RAW if possible. If not then adjust white balance manually
8. Filters - UV filters are not advisable for best image quality
9. If you're on a tripod, keep the ISO as low as possible to increase image quality and reduce noise. One exception to this may be if trying to make the shutter speed faster to reduce the effects of movement and blurring in your image. For example if you want to avoid blurred branches in trees swaying.

And here are a couple of examples of pretty much the same scene, taken 2 years or so apart.

1. A straight shot, taken to try to reduce blown highlights. 5 seconds at f8



2. A blended shot (using Exposure Fusion in Photomatix), taking 5 shots at differing shutter speeds at f11



Now there is a slight difference in image quality from the Nikon D90 and 18-105mm lens in the first shot to the D700 and 24-70mm lens in the second, but the big difference in image quality is the fact that the 2nd shot is blended, bringing out more detail and tonal range. It could be argued that tweaking in Photoshop can bring out the shadows more in shot 1, but this will also introduce noise, and the shadow details won't be great anyway.

As the camera captures more detail on the right 1/3 of the histogram (lighter colours) a range of several different exposures will bring in more detail when blended. For example, the longest shutter speed in the 2nd shot was around 20 seconds +. This blew all the highlights in the lit buildings but captured the detail in the shadow areas more. The fastest shutter speed was around 1 or 2 seconds and this captured detail in the well lit areas, but anything unlit was cast as black. Taking the single shot is a compromise.

At the end of the day, try getting a tripod and experimenting.

Good info Phil, the last shot is a classic.

Cheers

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Nikon D7000, D40X, Nikkor 18- 200 VR II, f3.5-5.6, 70-300 AF non VR, Kit Lenses.

Thankyou very much for your responses Phil. I love that first photo!

I'm afraid it's still not clear to me. You said "this is where the tripod comes in" to deal with a shallow DoF but how does that help?? Even if the shutter is very slow, isn't the depth of field still shallow?

awesome work Phil, need to sell wife and kids and give up work, I am not getting enough time for photgraphs

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Depth of Field is not linked to shutter speed at all.

If you have everything at a distance, then focussing near infinity will mean that your aperture is not so relevant. i.e. virtually everything will be acceptably in focus (as in the hand held shot previously posted). Therefore you can get away with handheld. Most lenses will not perform well wide open, but image quality will increase as you stop down by 2-3 stops before diffraction steps in and quality decreases again. As long as you are prepared to sacrifice optimum quality then you can get away with wide open and hand held sometimes.

If you have a subject that is close, then if you want to get everything in acceptable focus (near and far) then you will have to close the aperture down. This will obviously let less light in which will then require a longer shutter speed. Then you'll either have to use a tripod or push the ISO right up to possibly unacceptable levels.

For example, this shot was handheld. As there's nothing in the foreground and I'm focussing on the mosque, I could open up to f2.8, which allowed a 1/30th shutter speed at ISO1000. This gave acceptable sharpness.



Then this shot was also hand held. As I wanted the lantern in focus and the background to blur out, I opened up to f2.8 at a shutter speed of 1/80th second at ISO2500. If I wanted the background in focus as well, given the range to the subject, I would have had to stop down to f11-f16. This would require a tripod.



With this shot, I was on a tripod. This was with a 35mm prime lens, with a maximum aperture of f2. At f2, this shot was sharp where I wanted it to be, but too blurry in the out of focus areas as the target was so close to the lens. Therefore I had to stop down until I got the effect I wanted. f8 and 1/4 second exposure at ISO100. If I had ISO200 it would have been a 1/8th second exposure, ISO400 a 1/15th second exposure, ISO800 a 1/30th second exposure and ISO1600 a 1/60th second exposure which I could have taken hand held, but I wanted maximum quality so kept the ISO low. I can't find the f2 version of the shot, but that's 3 2/3rd stop faster, which would have given me a shutter speed of around 1/50th which again could have been hand held.



Hope this helps

Good advice and info so far from Phil - I thought I'd just add hopefully to the thread to help clarify...

Try thinking of night photography as two seperate types...there's handheld night photography, and there's long-exposure night photography. They really are two different types and styles, so the settings for each differ.

When taking handheld night shots, it is obviously of first priority to have the shutter speed be fast enough to allow you to handhold without shake or blur. That shutter speed will be dependent on you and your camera/lens - some folks can handhold 1/2 second, some struggle with 1/30 second...and stability systems in cameras or lenses can stretch out the hand-held times even longer. So aperture becomes a big factor - and the recommendation is usually to open it up as wide as it can go, and to consider using fast lenses with big maximum apertures. While the depth of field can be quite shallow depending on the focal length, this won't often impact a building or landscape shot with a short focal length as it is far enough away...it will affect closeups, portraits, and detail shots - though sometimes that shallow depth of field will be desirable. Also, ISO often has to be raised for handheld night shots, since even a wide open aperture in dead of night still isn't enough to get a fast shutter speed. Generally, folks first open the aperture as wide as needed, then if still not enough, start raising the ISO as much as needed but as little as possible.

For long-exposure night shots, noone's going to be steady enough to handhold, so tripods or fixed level surfaces to place the camera on become necessary. Since the camera will now remain steady no matter what, there need no longer be worry about getting fast shutter speeds, so ISO can be set to the lowest levels, and the aperture can be stopped down a bit if desired or needed. This will be dependent on how much light is in the scene, keeping or controlling highlight areas while still exposing midtones and shadows, and depth of field considerations. Of course, long exposures will cause any motion in the scene to streak or blur, so being conscious of any movement in the scene is necessary, to determine if it's acceptable or desirable - you may shorten the exposure a bit if you only have a small window to get the shot without movement (say, two people are walking into your shot in about 15 seconds, and you were going to do a 20 second exposure - you might dial back the exposure to 10 seconds, increase the aperture a bit, and take the shot so you can finish it before the people walk into frame to avoid their blur).

Once you're on a tripod, you also can consider multiple shots of the same scene, as Phil showed above - allowing you to do seperate exposures for highlights and shadows and any number of midtones in between and blend them into a single shot.

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Quote: "I'm afraid it's still not clear to me. You said "this is where the tripod comes in" to deal with a shallow DoF but how does that help?? Even if the shutter is very slow, isn't the depth of field still shallow?"

Hi EmyB. There is some excellent advice from Phil and others in this post. Not to mention some great photos!

One thing I would say is make sure you understand the relationship between shutter speed, ISO and aperture thoroughly and how adjusting one will affect the others. When Phil says "this is where the tripod comes in", he means that because the tripod is able to hold the camera perfectly still, you can now have the shutter speed as slow as you like without any blurring of the image. This means that you no longer need to compensate for the lack of light by opening the aperture wide up and having a shallow depth of field.

Anyway like I said, a very informative post from Phil and an interesting read.

First of all, I will say that truly excellent advice has been posted thus far, by people more experienced, by far, than me. I will contribute just a bit, because much of my limited experience has been gained shooting at night.

Going back to the original post, the mentioned recommendation to open the aperture to the lowest possible F-value is quite right, and spot on - open the aperture to the lowest value that gives you the depth of field you need, which is different than opening the aperture the lowest setting mechanically possible. As dubaiphil mentioned, shallow depth of field is not a limitation when the subject is at or near infinity.

If one needs a significant depth of field in low light, and therefore must stop down to f/11 or more, then a tripod becomes immensely important. I shoot crime scenes at night, and to show as much detail as possible, with things all scattered about, will stop down to f/16, or even to f/22 or more, and use a tripod and remote release. (When I manage to misplace my wired remote release, or am using two cameras, there is the option of setting the shutter to release after a 2-second delay.) If one's camera cannot record an exposure longer than 30 seconds, then, one may have to up the ISO, but if there is a bulb setting, the ISO can be kept low.

An interesting thing about long exposures is that people and animals can actually walk through your imaged area, and if they remain in motion, will be virtually or completely invisible in the finished image. This assumes they are
not carrying any form of illumination, such as a flashlight (USA) or torch,
for those speaking the King's English. Of course, moving vehicles and aircraft
will leave interesting trails of light across the image.

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Nice stuff. Love the more 'ancient looking' Dubai.

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Night photography is one of my favorite things to experiment with. The posted images look fantastic. You've really got the technique down.

Night photography is very interesting and exciting. If anybody wants to do effective night photography then he should use a tripod and remote shutter release. One should use high level ISO for testing exposure and composition. One should also use prime lenses and should avoid filters.

Only if you're doing long exposures would I agree with that.


If you're using an entry-level DSLR or something with a small sensor, is that really such good advice, especially if you want to reduce noise? Surely a long exposure or a wide aperture would be more desirable than ramping up the light sensitivity?


Why only primes? Yes, they generally are a bit sharper with fewer compromises for the optics compared to zooms but so much so that zoom lenses are unsuitable or at a distinct disadvantage for night photography? I don't think so. I'd happily take a sharp zoom lens with a big aperture over a prime with a tiny aperture. Why avoid filters? Some filters can be beneficial or even essential depending on what kind of night photography you're doing.

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