Blue Sky / No Blue Sky

I am trying to figure out why on some pictures I am getting a nice blue sky in one shot and not on the next. Here is what I am doing, please give me your thoughts.

I am shooting a Canon 30D with a 16-35mm, 2.8 lens and a Hoya Pro Digital Protector filter on it.

Blue sky picture was 1/250 sec., f/8.0, IS0 100, Flash DID NOT fire.

No-blue sky picture was at 1/250 sec., f/6.3, ISO 100, Flash DID fire.

This is one example, but it seems each time I used the flash for fill-light of my subjects on the bright sunny day, I lost my blue sky and blue water. What is causing the blue sky to go away when I use the flash? Or is it something else?

Is it just the sky that changes from blue to not blue? Or do other colours change slightly?

It could be in how you are setting your white balance.

If you have it set to Auto White Balance then when the flash goes, it should be using the 'flash' white balance (I believe). And when you shoot without flash it will analyze the frame and pick a different white balance.

EDIT: Sorry, ignore the above. I didn't notice that your aperture on the "no blue sky" shot was wider. The sky is probably over exposed.

post both of these pics up... the exposure is very similar... - only 2/3 stop...

i can only wonder if the composition has changed enough to make the difference... the fill flash should only alter the part of the image in which it has an impact on... like the foreground....

id be keen to see what you mean in reference to it happening many times.... were you shooting MANUAL - or AV? or what... are you sure of those settings from the exif on both?

My guess would be that your sky is overexposed in the 2nd one (that is typically why it will be gray or show no detail).

Your aperture on the 2nd one was larger with the same shutter speed and iso and I doubt the flash would have much effect on the sky (although I'm very new to this so I could be wrong).

You could look at GND filters or circular polarizers to try and help prevent this.

The no blue sky picture is set for a +2/3 stop exposure of ambient light. If the sky blew out this is why. Next time once the exposure is set correctly for ambient then don't change it when you turn on the flash.

My Flash exposure compensation was set at -1/3. I did not shoot the same scene with the flash on and then the flash off, but looking through dozens of pictures I can see that when the flash is 'on' the blue sky goes away and when the flash is 'off', the blue sky comes back.

There does not seem to be a noticeable difference in WB between the two pictures I got the EXIF info from, although they are different scenes. There was plenty of blue sky in each scene. My wife was shooting a Canon P&S and her blue sky was much better than mine. I have been playing with the RAW files in Lightroom and having trouble pulling any blue sky out of the background in the flash pictures.

Threads like this are useless without the images with EXIF intact. Seems obvious but there sure are a lot of them missing pics.

I have posted the pictures to my Smugmug site. Here is the link. The photo with the blue sky was shot WITHOUT the flash on. The other two are with a flash and at -1/3 Exposure Compensation set on the flash to keep from washing out their face.

http://afphoto.smugmug​.com/gallery/8763846_K​bh6Z

canonloader wrote in post #8211751
Threads like this are useless without the images with EXIF intact. Seems obvious but there sure are a lot of them missing pics.

I have posted the pictures on Smugmug. Wave your cursor over the larger picture and click on "info" to see the EXIF.

Smugmug is crawling along so I cannot see your photos. It might be an exposure thing or possibly white balance. If you are shooting in AWB then when you turn on the flash it might be draining the colour from the sky by setting a higher colour temperature.

Update : Smugmug still dead. Getting nothing. Everything else tickety boo.
Update : another 23 minutes elapsed and still nothing from Smugmug. I'm giving up.

Unsubscribing.

I looked at the images and as I suggested earlier in this thread, you simply overexposed for ambient in the shots where the sky is white.

If you had stuck with the settings of the blue sky shot then the sky would have turned out OK. Realize that a properly exposed blue sky is very bright and close to blowing out. When you went to an aperture 2/3 stops faster with no change to ISO or shutter speed you blew it out.

Your exposure is similar, but the compositions are not. Big difference between 16mm, 20mm, and 24mm. In the two without the blue sky, you where closer to your subject. The one with the blue sky you were further away.

The reason you got a blue sky is because you included more of the sky and less of the horizon. You would have need to greatly underexpose and use the flash for fill to get any color out of the sky in those two pictures. In the photo with the blue sky... look exactly how blue it is at the tree line and compare that to the top corners.

jacuff wrote in post #8211982
You exposure is similar, but the compositions are not. Big difference between 16mm, 20mm, and 24mm. In the two without the blue sky, you where closer to your subject. The one with the blue sky you were further away.

The reason you got a blue sky is because you included more of the sky and less of the horizon. You would have need to greatly underexpose and use the flash for fill to get any color out of the sky in those two pictures. In the photo with the blue sky... look exactly how blue it is at the tree line and compare that to the top corners.

What he said.

Here's a solution. Get LR2/photoshop, mask the sky, then apply -2/3 ev and probably increase saturation. Beautiful blue skies without much effort.

One other thing I notice is that on both the overexposed photos your shooting almost into the sun. The blue sky photo has the sun 90 degrees to you.

There are a few things you can do though besides exposure. A polarizing filter will help a little but a graduated neutral density filter will help a lot. It will reduce the exposure of the sky while leaving your subjects alone.

There are also some post processing things you can do. You can apply a software GND filter effect to blend two layers, the first exposed for the people and the second for the sky.