Sun Spots/Dirt on Lens at DVinfo.net

Mike Cornett · March 29th, 2005, 09:40 AM

It's been hard to see sun spots/dirt on my lens while shooting outside. Does anyone have any techniques for ending this little problem?

I realize I should probably bring a monitor with me or stop using the LCD viewfinder. Any other suggestions would be great.

Thanks for the help.

Owen Dawe · March 29th, 2005, 03:05 PM

A problem most of us have had. Frustrating to say the least.
We need to be hyper fussy about the front end of our lens. I recommend you have a clear filter on your lens. Sure it can get dirty but if you scratch it during your now over zealous lens cleaning habits you have only scratched the filter not your expensive lens.
To the problem with your present footage. You may be able to do a touch up with a rotroscoping programme. I'm on a tight budget and have used the one that comes as part of Media Studio Pro and have been able to touch out or disguise the odd spot or unwanted feature to a acceptable level. Spots are tricky to remove as you usually create a new one. I've saved several shots though in post production. One case of a shadow cast onto the set by a person standing just out of frame and another when a light stand was in view. There is probably better 'rotroscoping' software out there. Perhaps some body else will let us know what.

Don Palomaki · March 31st, 2005, 06:03 AM

The large depth of field make it difficult to avoid seeing the effects of dust on the lens when outdoors, especially if you have a filter on the lens. Do your best to keep lens clean, use compresed dry air to remove dust, or in bad cases use photo lens cleaning material, and try using a larger aperture to reduce depth of field - which may require you use the ND filter and perhaps a higher shutter speed.

Graham Bernard · March 31st, 2005, 11:01 AM

Don is quite right.

I'm now on a pilgrimage on the search for the way to get a DoF set as low as possible for most eventualities. This has meant me getting a matte box and a further range of ND filters. I can now get to 1.5ND and can open up the iris - in most cases - to 2.0. This gives me loads of DoF options and my camera craft has now reached another plateau! This camera just keeps getting me excited.

I know this has departed from the sun spot thing - but DoF is just too important an option not to keep mentioning it.

Grazie

Mike Cornett · March 31st, 2005, 11:57 AM

A big thanks for everyone's input. I'll mess around with those techniques.

March 29th, 2005, 09:40 AM	#1
Mike Cornett Regular Crew Join Date: Apr 2004 Location: Dayton, Ohio Posts: 43	Sun Spots/Dirt on Lens It's been hard to see sun spots/dirt on my lens while shooting outside. Does anyone have any techniques for ending this little problem? I realize I should probably bring a monitor with me or stop using the LCD viewfinder. Any other suggestions would be great. Thanks for the help.

March 29th, 2005, 03:05 PM	#2
Owen Dawe Major Player Join Date: Jun 2004 Location: Lake Tarawera, Rotorua, New Zealand Posts: 244	A problem most of us have had. Frustrating to say the least. We need to be hyper fussy about the front end of our lens. I recommend you have a clear filter on your lens. Sure it can get dirty but if you scratch it during your now over zealous lens cleaning habits you have only scratched the filter not your expensive lens. To the problem with your present footage. You may be able to do a touch up with a rotroscoping programme. I'm on a tight budget and have used the one that comes as part of Media Studio Pro and have been able to touch out or disguise the odd spot or unwanted feature to a acceptable level. Spots are tricky to remove as you usually create a new one. I've saved several shots though in post production. One case of a shadow cast onto the set by a person standing just out of frame and another when a light stand was in view. There is probably better 'rotroscoping' software out there. Perhaps some body else will let us know what. __________________ Owen

March 31st, 2005, 06:03 AM	#3
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,489	The large depth of field make it difficult to avoid seeing the effects of dust on the lens when outdoors, especially if you have a filter on the lens. Do your best to keep lens clean, use compresed dry air to remove dust, or in bad cases use photo lens cleaning material, and try using a larger aperture to reduce depth of field - which may require you use the ND filter and perhaps a higher shutter speed. __________________ dpalomaki@dspalomaki.com

March 31st, 2005, 11:57 AM	#5
Mike Cornett Regular Crew Join Date: Apr 2004 Location: Dayton, Ohio Posts: 43	thanks A big thanks for everyone's input. I'll mess around with those techniques.

March 31st, 2005, 11:01 AM	#4
Graham Bernard Old Boot Join Date: Aug 2002 Location: London UK Posts: 3,633	Don is quite right. I'm now on a pilgrimage on the search for the way to get a DoF set as low as possible for most eventualities. This has meant me getting a matte box and a further range of ND filters. I can now get to 1.5ND and can open up the iris - in most cases - to 2.0. This gives me loads of DoF options and my camera craft has now reached another plateau! This camera just keeps getting me excited. I know this has departed from the sun spot thing - but DoF is just too important an option not to keep mentioning it. Grazie