To filter light...that would mean to stop some coming through or to change it somehow. But what about when filters make MORE light than you want? Particularly when they reflect something else into the sensor that shouldn't be there...
I use the LEE filter system now. I used to use screw in ND filters, and variable ND filters, but I often got colour casts and strange X-patterns across the image, especially at wide angles. LEE are used by a lot of top photogs and I can see why. My own experience is that they are reliable, and any colour cast, if I get any at all, is one that is very slight and easy to fix. They are very pricey, but I am happy with the purchase nonetheless, (I just wish they were A LOT more afforable!) LEE are not sponsoring me, by the way. This is my own unbiased opinion, LEE: if you want to sponsor me...I would particularly like to try out your reverse grad filter ;^)
So on to the MUPPET MOMENT then...
You see, the problem with filters, especially the slot in kind, is that light can get between the filter and the lens. This is even more likely when you stack filters, say, using something like a Big Stopper and an ND grad. Light can get in between them and bounce around all over the place.
Have a look at the two shots below. The first, a composition before using filters. The second, the problem. You can just about make out the white writing from the front of the lens to the left of the image. I have also had examples of this problem where the numbers were readable, (but I deleted those shots long ago!)
My muppet moment, and this has been repeated muppetry, is that this problem occurred during the shoot, but even though I checked the images, I didn't notice the leaking light and extra reflections until I got home.
I recommend increasing the brightness on your rear screen and double check with your glasses ON if you normally wear them!
Yes, flag the light! Use a remote, the timer or a cable release, (we should be doing this anyway, especially with long exposures), and stand between the light source and the camera then hold your jacket or some other object to block the light. While doing this, make sure you are out of shot...vari-angle rear screens are useful as you can twist the screen and make sure you are out of shot as you position yourself.
Even holding a book next to the lens can do the same job!
Photography is all about light! So, don't be a MUPPET, get only the light you want!
Please share any comments you have about such problems of leaking light, either from filters, the eyepiece, (or anywhere else for that matter).
Also what filters do you use? Would you recommend them?
The Frustrated Photog.