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-   -   Low light, fast shutter speeds (http://www.pets.ca/forum/showthread.php?t=74646)

hazelrunpack January 11th, 2011 02:01 PM

Low light, fast shutter speeds
 
This winter I've been trying to figure out the manual settings on the camera but I'm running into a problem with low natural light. The sun is, of course, low because of the season but it's also usually obscured by clouds and/or swirling snow, so the natural light has been extremely low.

I was hoping to get some shots of goldfinches taking off (we have 200 or so around lately and I thought it might make a neat pic when they all swirl up at once) but even with a fast shutter speed, I'm having trouble with the low light. Should I be monkeying with ISO at the same time?

I'm almost desperate enough for lighting that I'm considering putting the external flash (which I've never used :o) to work.

(If it helps, I'm shooting a Nikon D90.)

exkalibur January 11th, 2011 08:00 PM

Hazel, which lens do you have ? Are you zoomed out to the end of the lens range ? You may want to increase the aperture (lower f/stop value) if you want to keep fast shutter speed or try to raise the ISO value. All depends on the range of the lens. The D90 is a nice camera but I haven't had the pleasure of trying it...I'm more familiar with the Canon.

Dee-O-Gee January 11th, 2011 11:16 PM

Crype! I just learned from Marko's photo thread that TV on my Canon doesn't stand for T.V.!!! :loser: :o :laughing:

Did you try using the "S" setting on the Nikon? :shrug:

marko January 12th, 2011 11:44 AM

[QUOTE=hazelrunpack;976035]This winter I've been trying to figure out the manual settings on the camera but I'm running into a problem with low natural light. The sun is, of course, low because of the season but it's also usually obscured by clouds and/or swirling snow, so the natural light has been extremely low.

I was hoping to get some shots of goldfinches taking off (we have 200 or so around lately and I thought it might make a neat pic when they all swirl up at once) but even with a fast shutter speed, I'm having trouble with the low light. Should I be monkeying with ISO at the same time?

I'm almost desperate enough for lighting that I'm considering putting the external flash (which I've never used :o) to work.

(If it helps, I'm shooting a Nikon D90.)[/QUOTE]

It DOES help to name the camera you are using - and it IS good enough to get the shot you want. Because birds are EVEN MORE jittery than cats and dogs klmccallum has learned the correct answer here :highfive: Shutter priority indeed! For birds, I would choose 1/500 or faster as my shutterspeed.

If the light is too low to accommodate that speed when you look through the viewfinder, It will say Lo. At that point you can raise the ISO. On your camera, I'd suggest ISO 1000 might be the maximum you can use before you see noise or graininess. IF at ISO 1000 and at a shutterspeed of 1/500 it still says LO - there's nothing you can do except wait for brighter light, add flash, or jack up the ISO even higher and live with the graininess.

In the intro thread, i mentioned that exposure is the balance of ISO, aperture and shutterspeed. It works as a mathematical formula that's not complex at all. here's just one example: let's say for this bird shot your settings are this:

ISO 200 F5.6 at 1/60

As mentioned 1/60 is too slow for birds. If you RAISE The ISO you make the sensor MORE sensitive to the light coming in. So if you raise the ISO from ISO 200 to 400, You'll need to change the shutterspeed to 1/125 (or something close). OR you'll need to change the aperture to F8. THIS IS WHEN YOUR CAMERA IS SET ON MANUAL.

When your camera is set on shutter priority the camera will do the compensation for you. Sooo if you input 1/60 and the ISO is at 200, the camera might give you F4 depending on the light available. If you raise the ISO by 1 unit to 400, the camera will change the aperture by 1 unit to F2.8 (It won't change the shutter speed in shutter priority because shutter speed is the variable set by YOU.) Just to be EXTRA clear F4 was the original hole, aperture or F-stop...but because you raised the ISO, we compensate with a SMALLER hole of F5.6 because the film sensor got more sensitive by 1 unit. Even though mathematically it makes no sense, it works. F-4 lets in 2x more light (or 1 full unit) than F-5.6

[I](Aperture numbers (the F-stop or the hole) can be confusing to newbies UNTIL you think of them as FRACTIONS. F-4 is a larger hole than F-5.6 Just think of it as a fraction and it makes perfect sense. Would you rather have 1/4th of a pie or an 1/5.6th of a pie? A 1/4 is the larger piece. F-5.6 is a larger hole.)[/I]

If you dial in 1/500 and the F-stop says Lo, try raising the iso by 1 "unit" or 2 units to see if you can get an aperture that does not say Lo.

Here are how the "units" work when they are in 'full conventional units" Your new digital camera can use units in between these standard units, but the compensation will always be the same. This means that if you change by 1/3rd of any of these "units" the camera will compensate by changing something else by 1/3rd to balance the exposure. This is when you are in a fully automatic mode or a semi automatic mode like shutter priority or aperture priority.

ISO - 100 (slow ISO speed) - 200 - 400 - 800 - 1600 - 3200 - 6400
S.S. - 1sec - 1/2sec - 1/4 - 1/8 - 1/15 - 1/30 - 1/60 - 1/125 - 1/250 - 1/500 - 1/1000 etc
F - F32 (small hole - think of it as a fraction) - F22 - F16 - F11 - F-8 - F5.6 - F4 - F2.8 - F2.0 (large hole) etc

Hope this helps and please let's investigate further if it does not.
Thx - Marko

hazelrunpack January 12th, 2011 01:56 PM

Thanks, klm, exkalibur, and Marko!

klm--that's what I'm starting to play with--the 'S' setting. With limited success so far. :D But I'm larnin'! :thumbs up

exkalibur, I'm using the 70 - 300 mm VR zoom most of the time when I'm shooting birds. So I've got the problem of low light exacerbated by the longer lens cutting out even [I]more[/I] light.

Marko, thanks for the tutorial!! Very interesting! I'm going to print this out and play with it :thumbs up With luck I'll get it figured out before the large flock disperses... :D

marko January 12th, 2011 05:19 PM

Glad to be of help.

You CAN use slower shutter speeds like 1/30 1/15 or 1/8 or 1/4 or 1/2 or even 1 full second.

But because your own hands introduce shake into the camera for these speeds, you'll generally need to put your camera on a tripod.

If what you are photographing is stagnant - ie a mountain, any speed will work well.

If it moves though, a dog, person or bird will be blurry.

For some things though, like moving water, you'll capture stagnant elements like some rocks and beautifully blurred water.

I just mention that because the technical aspects are boring but a brief understanding of them can get you really creative results.

That's all for today folks.

Thx - Marko

hazelrunpack January 18th, 2011 02:42 PM

1 Attachment(s)
The light is just too dang low. :frustrated: Guess I'll just have to wait for the next really sunny day...probably some time in, oh, April! :laughing: I did manage to accidentally catch this image of a northern shrike when it landed 35 feet from me in the sumac. Since it's a 'mini-hawk' in behavior, I had one glorious instant surrounded by the sound of alarm chips and whirring wings as a mixed flock of 150 small birds went up from under the feeders all at once! :cloud9:

[ATTACH]71653[/ATTACH]

Shutter speed of 1/800; ISO bumped up to 640. It's still pretty dark, but not too bad for a serendipitous shot of an uncommon bird. :D Missed it's take off, though, so blew the opportunity to find out if 1/800 will freeze moving shrike wings.

marko January 18th, 2011 11:08 PM

A hard subject to shoot HRP, decent job for sure.
When possible, always focus on the eyes :)

Dee-O-Gee January 18th, 2011 11:15 PM

Must have been a kewl sound to hear the flock go up from the feeders! :crazy:

Too bad you missed the take off. :(

I think I would get so excited to get that awesome take off picture that I would probably miss it anyway even if the camera was aimed at the flight! :frustrated:

hazelrunpack January 19th, 2011 05:21 PM

Ya, that's what's happening. I'm missing the take off, even if I'm shooting multiple frames per second--that feature shuts off after x number of shots and I'm still trying to flush the flock when it stops! :laughing: I have to get the timing down better. :o

Soundy March 21st, 2011 03:47 AM

[QUOTE=marko;976241][I](Aperture numbers (the F-stop or the hole) can be confusing to newbies UNTIL you think of them as FRACTIONS. F-4 is a larger hole than F-5.6 Just think of it as a fraction and it makes perfect sense. Would you rather have 1/4th of a pie or an 1/5.6th of a pie? A 1/4 is the larger piece. F-5.6 is a larger hole.)[/I][/QUOTE]

It's actually easier to remember (and understand, I think) if you write the aperture properly, AS a fraction - ie. f/4, f/5.6, etc. The reason it's written this way is that the diameter of the aperture IS a fraction of the focal length (commonly represented by "f").

Therefore, if your focal length (f) is 100mm, at f/4, your "effective" aperture diameter is 100/4, or 25mm. At f/5.6, the aperture diameter is 100/5.6, or about 17.86mm. If you go to f=200mm, at f/4, your aperture is then 200/4, or 50mm. And so on.

An interesting thing to remember as well: every two "stops" is a doubling or halving of the ratio: f/8 is two stops smaller than f/4, and f/2 is two stops larger. Going down two stops from f/5.6 gives you f/11 (rounded off); two stops up is f/2.8. And so on.

The math makes even more sense if you extend this: at 100mm and f/4, for example, you have an aperture diameter of 25mm, or a radius of 12.5mm. Calculating for the area of a circle (pi*r^2), your aperture area is then 490.875mm^2.

Go down one stop to f/5.6, and you get a diameter of 17.86mm, radius of 8.93... and an area of 250.446mm^2... or very close to half the area = half the light allowed through (numbers are all rounded, BTW, including pi - if you don't round things off it's a lot closer to exactly half).

One more stop, to f/8, and the area works out to 122.718mm^2 (rounded off), which is even closer to exactly 1/4 the area of the f/4 aperture.

hazelrunpack March 21st, 2011 02:04 PM

Thanks, Soundy! Very good illustration of how the availability of in-coming light changes as the lens gets longer...and explains why at maximum zoom my light levels in winter just aren't sufficient for what I was trying to do. :o I never did get my hundred-finch take-off pic. But it gives me something to shoot for in future. :D

Soundy March 21st, 2011 03:13 PM

If you look at the lens marking, you see how most lenses list a range of apertures along with the focal length... like my Canon EF-S 17-85mm, also lists "1:3.5-5.6" (same as "f/3.5-f/5.6"). That tells you the maximum aperture at each end of the zoom - at 17mm I can get up to f/3.5; at 85mm it's only f/5.6.

Higher-end zooms are often designed to maintain a constant maximum aperture through their whole length (at additional cost, of course), but the vast majority of zooms have this "limitation".

Soundy March 21st, 2011 03:58 PM

BTW, something else you might want to try is shooting in RAW - it will usually let you shoot a little faster and pull some more details out of the shadows in post-processing. A good app light Lightroom will make working with it a lot easier.

hazelrunpack March 22nd, 2011 01:00 PM

I do shoot mostly in RAW these days, but I'm thinking of going back to JPG Fine... RAW is so difficult to work with...but it might just be that I just got PhotoShop Elements and am having a hard time trying to figure it out. I get how to adjust photos, but I'm not sure how it's storing the files or where or if it's making copies... :o Anyone have any insight on how PSE handles files? How it does the housekeeping might make a big difference in how I want to catalog things... My biggest questions right now--does importing an image from a file create a [I]new[/I] copy of the file or is it just linking to the image in the original file?

Second question: when you create a PSE album of images imported from an existing file is that created a new collection of images that you can access on your hard drive even if PSE is closed? Or is it just a set of links kept in PSE that point to the images in their original place on your hard drive?

:o

Yes, I obsess over details like this, but PSE really seems to be impacting the performance of my machine and I'm hoping to tailor the process for speed. :D

exkalibur March 22nd, 2011 01:51 PM

Hi Hazel
I use lightroom from Adobe..but PSE works close to the same way. Organizer doesn't make a new copy of your files, it just uses a link to them and keeps a thumbnail for itself (and the pic info). It's the same for albums or collections : it creates a symlink to the files..hope I made it clear enough.

Regards

hazelrunpack March 22nd, 2011 01:55 PM

Excellent!!! Thanks, exkalibur! So probably the reason everything runs so slowly when PSE is open is program overhead, not overutilization of available file space :D

Alrighty, then, I'm not going to worry about it and just dive in.... :) Wish me luck! :o

exkalibur March 22nd, 2011 01:55 PM

As a side note...when you work with RAW files and do any kind of editing/changes on them, it doesn't change the original RAW file..it creates an XMP file that contains the modifications you have made..so if you move any of the raw files, remember to move the XMP files as well.

hazelrunpack March 22nd, 2011 01:56 PM

Oh, good point! I do remember reading something about that somewhere. Thx, ex!

exkalibur March 22nd, 2011 01:57 PM

And don't forget to archive your files onto DVD or external drives...sucks to lose them to a hard drive crash...

hazelrunpack March 22nd, 2011 02:00 PM

madame hazel is paranoid--she makes mirror back ups to two separate 500G hard drives. :D madame hazel and technology don't coexist well, so we've adopted multiple redundancy archiving out of necessity. :laughing:

exkalibur March 22nd, 2011 02:04 PM

But madame Hazel sure seems comfortable using techno-geek terminology..:laughing:

hazelrunpack March 22nd, 2011 02:07 PM

madame hazel used to be a computer operator in an earlier life. :p We're talking mainframes...which should tell you how much earlier that might be...but keep it under your hat, please! :laughing:

exkalibur March 22nd, 2011 02:19 PM

I know the feeling...the first program I wrote was in the form of a punch card..on a remote terminal hooked up to the University of Montreal computer..

hazelrunpack March 22nd, 2011 08:45 PM

Remember the M6800 and octal? Themz wuz the dayz.... :laughing:

exkalibur March 22nd, 2011 09:56 PM

Thank god DOS and Basic came along....and that guy that said that we'll never need more than 64k of ram....

hazelrunpack March 22nd, 2011 10:27 PM

:laughing:

Dee-O-Gee March 22nd, 2011 10:35 PM

Oh my!!! I'm going to need to print out all of these helpful tips to get a feel for my new DSLR...especially with fast moving subjects. :o

Great pointers exkalibur and Soundy! :thumbs up

:thankyou:

hazelrunpack March 22nd, 2011 10:45 PM

Too bad we aren't nearer, klm--we could practice together! :D


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