What am I seeing here?

[benlonghair]

Took this last night. I like the photo, but that green blob in the lower left hand corner is ugly as hell.

I think it's lens flare coming off my UV filter (which I have taken off my 35 and now will take of my 18-55) but I'm not sure. It's definatly not stuff on the sensor because it's in the same place on the photo regardless of the orientation of the camera.

Opinions?

 

[rpm]

i dont see the blob to be honest. but also you should consider leaving the UV filters as they are great in protecting your lens - i doubt whatever you may be seeing is caused by them unless they're very very cheap filters. are you sure it also might not be the environment itself? as what you're seeing was actually there?

 

[Boomn4x4]

i dont see the blob to be honest.

I see it just fine. Its between the 5th and 6th row from the left.... can't tell you what it is though.

 

[rpm]

oh wait i see it now. thanks for that...

i have no clue what that is. are your UV filters clean?

otherwise it could be the sensor. the fact that it doesnt change with orientation does suggest it being possible sensor issue (maybe?) - long stretch though. im assuming it just appeared recently? and you've tried a few test shots after?

 

[Overread]

Wait when you say its not on the sensor because its in the same position do you mean that the greeny blob appears in that same spot in each and every (or many) shots you take no matter at what angle and such - or - that you took several shots of that scene and the green blob was in the same geographical spot of each shot and not tied to a prat of the frame itself.

It does look like and odd green dustspot to me - odd because they are normally not green but black where they block the light.
If its certainly not a dustspot or any other sort of mark on the sensor then a flare it would have to be, though its far less defined than many that I have tended to see.

 

[benlonghair]

Wait when you say its not on the sensor because its in the same position do you mean that the greeny blob appears in that same spot in each and every (or many) shots you take no matter at what angle and such - or - that you took several shots of that scene and the green blob was in the same geographical spot of each shot and not tied to a prat of the frame itself.

This shot was shot in portrait orientation. The blob is lower left corner. If it were dust on the sensor, I'd assume that when I flip it to back to landscape the blob should be up in the sky in the upper left corner. It's not. On the landscape shots, it's... wait for it.... lower left corner (although more centered). Didn't see it while I was shooting or I would have dropped the UV filter and seen what that did. I can see no dirt on the rear element, front element or any other part I can see without exposing the sensor.

To make matters worse, I tried to heal it out with Gimp and it does horrible things to the red and blue channel.

 

[Overread]

Sounds like a lightflare/glare then - if it were something on the lens itself it would have to be pretty large in order to make sucha noticable impression on the image.

As for healing it out - if that fails I think your next best bet is to combine clone and heal (not spot heal) and make a more major job of removing it from the image.

 

[KmH]

No doubt it's a flare from the brightest part of the scene, the bright yellow patch above and directly in front of the flare just beyond the deep shadow falling across the rows.

There is also no doubt it's caused by the UV filter.

This statement by rpm

but also you should consider leaving the UV filters as they are great in protecting your lens

is not always true.

Obviously in your shooting situation here, a UV filter was totally unnecessary for 'protection'.

I would submit, the range of shooting situations where a UV filter actually offers protection are few and far between for the majority of photographers.

Did you see the video of the guy pounding on the front of his lens with the hammer? The lens didn't break.

 

[rpm]

No doubt it's a flare from the brightest part of the scene, the bright yellow patch above and directly in front of the flare just beyond the deep shadow falling across the rows.

There is also no doubt it's caused by the UV filter.

This statement by rpm

but also you should consider leaving the UV filters as they are great in protecting your lens

is not always true.

Obviously in your shooting situation here, a UV filter was totally unnecessary for 'protection'.

I would submit, the range of shooting situations where a UV filter actually offers protection are few and far between for the majority of photographers.

Did you see the video of the guy pounding on the front of his lens with the hammer? The lens didn't break.

that sounds hard to believe...i doubt he really pounded it. have a link?

but i use it to avoid any sort of scratches, be it sand, be it when im hiking, dirt, if i get bumped, its a nice protective layer....it effects IQ at most marginally and it doesnt hinder the output in anyway from last ive read on it. i never said it is a must or you should, i just said its a great protective layer, which it is no doubt. despite what situation you may be in. for me i rather have peace of mind than anything unless im indoors and certain that i will be very careful with things and there wont be any wild cards.

 

[benlonghair]

that sounds hard to believe...i doubt he really pounded it. have a link?

but i use it to avoid any sort of scratches, be it sand, be it when im hiking, its a nice protective layer....it effects IQ at most marginally and it doesnt hinder the output in anyway from last ive read on it.

Here's an interesting article about front element damage and image quality.

I also had problems with flare on my 35mm 1.8 when doing a long exposure of the sky at night. I will not be putting UV filters on unless I'm doing something that might really hurt the lens.

 

[Overread]

http://www.thephotoforum.com/forum/...ters-your-lenses-do-you-really-need-them.html

Generally speaking a lens hood offers you a lot more protection for no image quality loss (on fullframe some hood can use a little vignetting (shadows in the corners) but is easily correctable in editing).
When it comes to things like sand and salt you have to take into account your shooting location. If you are on a sandy beach chances are you should be fine - if its a standstorm or strong wind then yes a filter would be suitable (as well as a cloth cover to go over the setup to ensure sand does not get into the workings of the camera either).
Again with saltspray if you are working in the sea or on it a filter is certainly advisable along witha waterproof cover (even the fully weathersealed gear is not totaly waterproof and dried in salt residue can be an expensive nightmare).

In the end when it comes to filters you can use them all the time, some of the time or not at all but if you do use them you want to go out and get a topbrand filter. The $/£5 ones are just going to degrade the light entering the lens (leading to problems similar to the above for example - but autofocus and sharpness can also be drastically affected) - multicoated and topbrand filters. You've spent good money on the glass in the lens now spend good money on the glass you put infront of it.

Finally remember that a filter won't stop a stone or strong impact - infact in such cases a filter can often make things worse as the thinner filter glass shatters and then scratches over the surface of your lens. Filters are there as quick wipeclean solutions and small dirt/mark protection - don't bank on them stopping stones or paintballs (your hoods for that)

 

[AlexL]

Out of curiosity, what filters do you use?

I get so confused of when to use a filter, the benefits of a filter, or whether or not it is effective from all the discussion and from what people tell me.

Let me look up the on kenrockwell.com on this as everyone would agree it is the bible of photography.

 

[KmH]

There are different kinds of filters.

UV filters are pretty much useless you are at high altitude, 10000+ feet, or are trying to photograph things that have materials that flouresce under strobed lighting (some wedding dresses).

There are Circular polarising filters (CPL). They can help control unwanted reflections form smooth surfaces and saturate many colors. CPL's have a rotateable front element so you can control the effect to a degree. CPL's work best when the main light source (like the Sun) is at 90° to the lens axis and no more than 30° above the local horizon.

Neutral density filters (ND) are often used to darken a Sun lit scene so a slow shutter speed can be used, like to photograph a waterfall so the falling water is rendered as silky smooth from motion blur.

Graduated neutral density filters (GND) are used when part of a scene is bright and the other part is dim, like a sunset. The darker part of the filter is placed over the bright sky and the clear part is placed over the foreground.

Unlike in the days of film, colored filters serve much less purpose in digital photography.

 

[Derrel]

It looks like it is a slightly out of focus water drop or water spot on a UV filter. It really looks to me like a water drop is what caused it. On "some" lenses, like the old Nikkor 55mm f/3.5 and f/2.8 Micro-Nikkor lenses, where the front element of the lens is over one inch behind the filter threads (deeply recessed front element designs), it was somewhat common to get the UV filter and junk on it almost into the focused zone when shooting at closer distances and at small apertures...so with those lenses, it was always considered good practice to never use a UV filter!

Anyway...had it been raining there? I see a rainbow...maybe you got a drop of water on the lens front...that's what it looks like to me...