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View Full Version : Should I worry about scratching my light meter lens?



Riverteeth
6-Jan-2008, 02:32
OK, after much research I just purchased my first independent light meter with a built in spot (Sekonic 758DR), and I'm really looking forward to using it. I was surprised when the employee who sold it to me insisted that I would need to put a UV filter over the spot lens to protect against damage. I thought, what the heck, it's the light meter, as long as I take decent care of it, and put the included lens cap on it between uses, why should I worry that much about the possibility of maybe scratching it a bit. The employee said that a slight scratch to the lens could affect the meter reading. This sounds unlikely to me, but then maybe it's not a bad idea to protect the unit for the day I'll want to sell it. Does anyone know if what she said has any merit?

Gene McCluney
6-Jan-2008, 04:06
Minor scratches on the lens of a light meter will not affect the accuracy. It sounds like he has been taught to try to get "value added" sales items bought with every purchase. There is a huge profit margin in filters and other small accessories.

lenser
6-Jan-2008, 04:26
I agree completely with Gene. I guess I could imagine that a thoroughly scratched lens (as in taking sandpaper to it to the point of making it opaque), might create a near incident effect instead of a spot reading, but then you wouldn't be able to see through it anyway.

You're not worried about sharpness as with a lens, only light transmission. He's just trying to sell you up.

Matt Blaze
6-Jan-2008, 04:49
What Gene and Lenser said.

I''ve never heard anyone seriously recommend putting a "protective" filter over a spot meter lens before. (Doing that with camera lenses is dubious enough, but at least somewhat defensible. But certainly not with a spot meter.)

So don't worry about your spot meter lens. If you want something to worry about, worry about the (either dishonest or clueless) dealer who tried to sell you a filter for it.

Riverteeth
6-Jan-2008, 04:59
Thanks everyone. On a similar vein, reading through Sekonic's own material on the meter, I see that the threads on the spot meter lens are actually for a lens hood / step up ring (for other filters). Is flare a big concern when metering? Seems like a good technique if one were worried about flare affecting the reading would be to use my left hand as a hood when taking a measurement...

Preston
6-Jan-2008, 08:11
If you set up your camera and believe that flare will be a problem, then it will likely be a problem when you meter from the camera 's position. Therefore, a shade of some kind or other will be called for.

I have used my free hand to shade the meter lens (a Pentax Digital). I have also heard of some folks using a toilet paper tube as a lens shade. One would simply have to careful to not block the incoming light one is trying to meter.

-PB

Dave Parker
6-Jan-2008, 12:21
Boy, if I worried about that, I would never use my meters, all my meters have various scratches and such on the lenses, and my incident meters have scratches on the domes and flat discs, they still read fine...I guess I need to buy some new ones, just take care of them normally and you should be fine.

Dave

Eric Woodbury
6-Jan-2008, 12:25
The scratches on your meter need to match the scratches on your lens.