Digital Camera (ISO) Question?

Ok I need help here guys. Here are two different Photos I took yesterday.
[image]http://i5.photobucket.com/albums/y177/BNSFrailfan/DSC00018.jpg[/image]
and
[image]http://i5.photobucket.com/albums/y177/BNSFrailfan/DSC00020.jpg[/image]
The first one is way on the dark side. The second one is much brighter because the sun was out. How do I get a brighter shot when it is very cloudy like it was yesterday? I was useing an ISO of 200. I have many choices of useing the ISO. Auto,80,100,200,400,800 And 1000.Whice ISO should I use when the sun is shineing? And which ISO should I use when it is Cloudy? Thanks,Allan.

On a bright sunny day, you generally
want to use ISO 100. For a moderately
cloudy day, try ISO 200. On a day
with heavy overcast, use ISO 400 or
stay home. [8D]

Dave
http://www.railpictures.net/showphotos.php?userid=920

The short answer is use the lowest ISO that will get the job done. Getting the job done usually means a fast enough shutter speed to stop motion, and stopping the lens down enough to improve its performance and get some more depth of field.

Looking at the EXIF data for the first image, you used a shutter speed of 1/320, an aperture of 6.3, and an ISO of 80. The reason it’s dark is that the overcast sky acts sort of like a giant softbox that itself is very bright but doesn’t throw out as much light as a normal clear sky. The sky threw your camera’s meter off and it exposed for sky rather than for your subject, the train. The way to get around this is to adjust your camera’s exposure compensation into the + range, something which virtually every digital camera I’ve ever seen(including the one built into my cell phone) allows you to do. Check your manual to see how to do this. 1 stop(+1) will probably be about right, although you may need to go to +2. Adding one stop will bring you to 1/250 and 5.6, which is perfectly fine. For your purposes, you can really even use any F-stop you need to, as you’re likely at or near infinity and depth of field isn’t so much of an issue.

By the way, my favorite film is Kodak E100G, an ISO 100 speed slide film. Most of the time, I find it to be perfectly adequate for any outdoor photography that I do. I generally use ISO 400 and no flash inside, although most compact digitals(non-SLRs) aren’t anywhere near the quality of ISO 400 print film.

ben10ben has it right, the differing lighting fooled the camera’s auto-exposure. It’s not a problem with the ISO setting. Are you showing uncropped images? If not, it would give us a better idea of the percentage of sky in the source image. To fix, you either exposure compensate, usually about 1.5 stops, or change the camera’s scene setting, if it has one.

On days when you have that backlit white kind of sky, it throws off the meter and makes it think that the overall scene is brighter than it really is… thus the dark foreground. Try bumping the EV compensation up .3 to .7 stop in those conditions, and it should look better.

Dave
http://www.dpdproductions.com

  • Featuring the TrainTenna Railroad Scanner Antennas -

Also, your camera may allow you to change from a multi-point light meter to a single point meter. Using the spot meter function allows your camera to adjust its settings to the subject rather than the whole scene. No matter how you do it, if you meter for the engines you will probably blow out the sky. The answer to that problem is a split neutral density filter. You fit it over your lens and adjust it to darken the sky while allowing full light to be sensed in the darker areas.

You don’t say what kind of camera you have but the best thing you can do is to take the manual out with you (shock horror), and take lots and lots and lots of pictures using all of the different settings under different conditions. You’ll eventually get the hang of it.

It’s a Sony DSC-S600 Camera. I got to the ISO. It say Auto ISO. But I can’t seem to change the ISO speed. Ill figure it out some how.

Never mind. I FINALY figured it out. I lowered the ISO to 100 and increased the Sharpness and also the Contrast. Now I will take another shot tomorrow. Thank you everyone for the help. Thank you. Allan.

You may want to reconsider changing your in-camera contrast and sharpness. It only takes a second to apply the unsharp mask in photoshop, plus you get a whole lot more control on amount and effect. You also want all the dynamic range you can get, and upping the contrast in-camera might make it easier for you to blow your highlights. Not only do blown highlights look really nasty with digital(color fringing), but they’re also totally unrecoverable(unlike print film). Once again, it just takes a second to up the contrast in Photoshop, and you get a lot more control.

You’re generally better off with the least amount of in-camera processing possible. It’s really easy to add sharpness and contrast, but it’s really hard to take them away once they’ve been done. In camera processing also bogs down your camera’s CPU and makes things slower.

I agree with ben10ben; I have tried both ways with my digital and generally seem
to get much better results letting the camera do it’s “own thing” and compensate
with what ever editing program I’m using.

Hows this look guys? I set the ISO down to 100 and increased the Sharpness and the contrast. Allan.
[image]http://i5.photobucket.com/albums/y177/BNSFrailfan/DSC00038.jpg[/image]

Alan:
Does your camera have a provision for manually adjusting the aperture opening or the shutter speed? You should be able to get a well lighted photo with an equivalent ISO (sensitivity) of 200, however, you will have to open the shutter aperture, lower the shutter speed, or both to do that. By increasing the film speed you geta grainier picture, and same holds true for increasing the equivalent ISO sensitivity.

To manually get the correct exposure for an average subject think about the “Sunny 16” rule; that is 1/ film speed with an aperture opening of f/16. That is with an equivalent ISO of 200 the correct exposure for an average subject on a sunny day would be 1/200 second at f/16. However, on an overcast day you will have to open the aperture wider, perhaps to f/8
(at the same shutter speed) to get a well lighted photo

Perhaps there is a simpler way of expressing the problem.

The photo is not dark because the scene is dark, but because the sky is brighter than the train. You can change the ISO setting from 100 to 1000, and the picture would look the same, because the exposure is “correct” as far as the camera meter is concerned.

On my camera, a Canon 10D, it is possible to dial in an “offset” of one or one half “stops” (a stop is a halving or doubling of aperture or shutter speed).

In the example you show at the beginning, adding one stop of over exposure would probably give the correct appearance for the locomotive, but the cloud detail will be lost, of course.

I expect that with less skylight visible, one half stop over exposure would do.

M636C

“In the example you show at the beginning, adding one stop of over exposure would probably give the correct appearance for the locomotive, but the cloud detail will be lost, of course.”

And that’s the nature of digital photography. No matter what, that’s one area where print film is now and always will be superior.

And to go back to what I was saying earlier, dialing more contrast into the camera may make it easier for this to happpen.

What are you doing out shooting UP stuff? Whistles as I hide this shot.

http://uptrain.rrpicturearchives.net/showPicture.aspx?id=354690

I don’t agree with that. In capable hands with perhaps a little post-processing digital sensors can kill print film in terms of dynamic range. This is especially true if one shoots in RAW mode and does a “double” conversion of the RAW file and combines the two in Photoshop after the fact.

Still, even shooting in JPEG, there’s considerable dyanmic range available. Watching the histogram on the digital is really the key here. Take this shot for example:

I was out hiking in RMNP without a tripod. I should’ve been shooting in RAW, but I didn’t think it was that great of a shot and just shot straight JPG. I watched my histogram, and tried not to clip too much from either side. Afterwards, I decided I liked it, and tried to rescue in Photoshop. It’s not the greatest PP job ever, but I still like it, and I doubt I would have been able to pull it off with any kind of film. If I had really been trying, I would have shot on a tripod in RAW (and possibly multiple shots with varied exposures for the various parts of the image…not possible for moving trains, but useful for landscapes).

Just my 1/50th of a dollar of course.

That may be true, but you do have to admit that they’re both very different animals.

Had I been making the same shot in the initial post with print film in my T90, I would have just spot metered and averaged the train and the ground and let the sky fall where it wanted. The sky may have blown out on the print, but I probably could have salvaged it with some careful scanning.

I’m not even sure how to go about doing the same thing with digital, although admittedly my experience doesn’t go much beyond using a point and shoot. I would guess that you would expose for the sky and then try to bring up the shadows. Since many point-and-shoots don’t have the ability to record in RAW, you may not be able to do this. Correct me if I’m wrong on this.

And if you were using slide film, you’re pretty much out of luck on dynamic range. I would have, again, metered the train and ground, then tweaked it a little bit, and hope that the sky wouldn’t blow out completely.

By the way, great shot, Chris.

Ben,

Some P&S’s offer RAW, some TIF (which doesn’t offer the flexibility of RAW, but doesn’t suffer any image degradation due to JPG compression), and some just offer JPG. It’s usually based on price, though some manufacturers are better than others. Most P&S’s (except the very cheapest) do offer histograms, and some even allow live histograms (which is a treat that DSLR users don’t get…just based on the nature of the beast).

Spot metering is useful, but even on the couple times I’ve played with the Canon bodies that have it (1 Series, 5D and 30D), I always find myself using the histogram more than the spot-metering. Any type of metering shows what potentially lies in the camera frame. Meters can still be tricked by certain conditions, though. A histogram shows what has already been recorded in the frame. Granted, while making quick grab shots, there isn’t a lot of ti

OK I didnt see anyone say it, So I am going to do it.

ISO is the speed at which the image is recorded. The higher the number, the faster it goes, but if yo use a faster ISO, you will lose you quality and it will become grainy (on film), or pixelated (Digital). The was I use my ISO setting on my Canon 20D is when I do night shots, I want to be sure to get as much light as possible, so I use my highest ISO being 3200, But if I am out in the desert here on a clear day, I will use say, ISO 100 or 200. When using Manual mode, using a high ISO will allow you to use a faster shutter speed or a smaller Aperature setting if you are using a SLR camera. Higher ISO is also a little better for action shots becasue if the shutter speed thing. ISO started for film, which is why we have different film speeds and they print on the box what it is best used for.