Is my new lens fooked?

cornbb

I bought a Canon 50mm f1.8 "nifty fifty". I'm mostly happy with it but I'm noticing some weird artifacts - when there are strong highlights in a photo (the candles in this example, I'm seeing bright greenish spots in the image, mirrored across from the centre point of the image (hope that makes sense).


I took this at f1.8 1/50 with Canon 500D.

Am I doing something wrong or is my lens faulty?

5uspect

It's probably just lens flare:
http://www.flickr.com/groups/canonef50mm/discuss/72157601785735075/

Are you using a filter?

cornbb

Ah, that's exactly what it is. Yes, I'm using a UV filter. I'll try reproducing the issue without it. Thank you so much

Zillah

Screw UV filters...

...off your lens, because they're unnecessary.

cornbb

I use them solely to protect my lenses. But perhaps they're not worth it, if they're producing such negative effects.

BTW I did a quick test; that did the trick. I'm not seeing any flare without the filter.

Alanstrainor

Zillah wrote: »

Screw UV filters...

...off your lens, because they're unnecessary.

I have one on my lens, i always keep it on to protect the lens more than anything else. I'm not exactly an expert on these things though...

hbr

cornbb wrote: »

Yes, I'm using a UV filter.

That's the most likely cause of flare and reflections. There isn't much point in
putting a UV filter on a nifty fifty. The front element is quite deeply recessed
so it doesn't need protection. You can get a high quality multicoated filter
which will be less prone to reflections, but it will cost almost as much as
the lens. If you want to protect the front element and also reduce flare and
reflections, get a cheap hood on eBay.

harryhyden

Use filters

kelly1

I've seen something similar where you take an overexposed shots of the moon and you get another ghost image of the moon appearing. It's caused by light bouncing off the sensor, hitting the rear element of the lens and bouncing back to the sensor again. What you're seeing could be this.

cornbb

kelly1 wrote: »

I've seen something similar where you take an overexposed shots of the moon and you get another ghost image of the moon appearing. It's caused by light bouncing off the sensor, hitting the rear element of the lens and bouncing back to the sensor again. What you're seeing could be this.

I've had that problem too. But in this case the problem was rectified by doing away with the filter.

kelly1

cornbb wrote: »

I've had that problem too. But in this case the problem was rectified by doing away with the filter.

OK, sound like the light is bouncing off the front element and hitting the filter and bouncing back.

dmg1982

A lens hood is better protection (IMO) for the front element of a lens and it serves to improve image quality rather than degrade it.

Most digital cameras have a UV filter built-in over the sensor, so there's no need for them (IMO).

dmg1982

kelly1 wrote: »

OK, sound like the light is bouncing off the front element and hitting the filter and bouncing back.

Pretty much... I believe the light reflects off the sensor during exposure too, made visible by having the filter in place.