Quick Question - Can I Keep My UV Filter On At Night ?

Yup. I agree. I'd keep it on unless there's a danger of bright lights causing flare, but you can test this to a degree yourself.
 
Bright lights and dark backgrounds are a good recipe for disastrous flare and ghosting, but chances are you won't see it in the viewfinder. Only in the finished pic or in live view.

Main problem will be light bouncing off the sensor and then being reflected back off the rear of the filter as a ghost image.

Take the filter off (and preferably throw it away).
 
All filters, even the very best, will cause some additional flare and ghosting. With a good filter this is normally too small to show up. But if you've got bright lights and lots of dark areas (which sounds very likely) then you will see these effects, and they won't look good.
 
All bits of glass, elements, the lot will add to the chances of flare but filters are flat so not much of a problem as a bulbous wideangle front end!

Yes, you can keep it on all the time - just like your socks!
 
chuckles said:
All bits of glass, elements, the lot will add to the chances of flare but filters are flat so not much of a problem as a bulbous wideangle front end!

Yes, you can keep it on all the time - just like your socks!
Click to expand...

The main problem is that they are flat!
 
HoppyUK said:
The main problem is that they are flat!
Click to expand...

- but, they will only catch light in one plane whereas a huge convex blob up front will stand a chance of catching it all over the place. I try not to use filters at all if I can help it.
 
HoppyUK said:
The main problem is that they are flat!
Click to expand...

chuckles said:
- but, they will only catch light in one plane whereas a huge convex blob up front will stand a chance of catching it all over the place. I try not to use filters at all if I can help it.
Click to expand...

All of Canon's big telephotos have what is, in effect, a protective filter as the front element. And it's curved - so that internal reflections don't end up on the sensor. A flat glass surface is much more likely to send unwanted reflections into unwanted places.
 
chuckles said:
- but, they will only catch light in one plane whereas a huge convex blob up front will stand a chance of catching it all over the place. I try not to use filters at all if I can help it.
Click to expand...

See Frank's post above.

With bright lights against a dark background, you will get ghost images. Almost guaranteed. It's a digital effect, because unlike film, the sensor is very shiny. Light reflects off it, and the rear of the filter bounces it back as a repeat ghost image. That's what's happening in these examples.

Folks that say filters don't degrade image quality are almost always talking about sharpness, which is rarely seriously affected. And they never take two pictures side by side, with and without the filter, to see what's actually happening. Try it with any bright lights against a dark background, or a sunset :eek:

Two pictures with a Canon 17-40L, one without a filter, and the other with a multicoated Hoya Pro-1 UV - one of the best UV filters you can get.

IMG_0425.jpg


IMG_0424.jpg
 
Considering I was shooting from a car for the most part ghosting was the least of my problems..... ( anoyingly so )..... I really didnt have the oppertunity to walk around and do a proper long exposure BUT those that did come out I dont think had that problem.... even the ones affected by me moving at the time....

Any way - here they are.... I love the tram one my self.... well pleased with that.

Blackpool Illuminations 2010 by letscommunicate, on Flickr

Blackpool Illuminations 2010 by letscommunicate, on Flickr

Blackpool Illuminations 2010 by letscommunicate, on Flickr

Blackpool Illuminations 2010 by letscommunicate, on Flickr

Blackpool Illuminations 2010 by letscommunicate, on Flickr

Blackpool Illuminations 2010 by letscommunicate, on Flickr

Terran
 
You must log in or register to reply here.
Back
Top