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Canon EOS Crop Sensor for HD
APS-C sensor cameras including the 80D, 70D, 7D Mk. II, 7D, EOS M and Rebel models for HD video recording.


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Old June 20th, 2010, 06:24 AM   #1
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Do cheap filters lessen sharpness of images?

I have some basic Hoya UV Filters over my lenses but wondered if having these on would materially affect the quality of the video shot by making the picture quality less sharp?
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Old June 20th, 2010, 07:32 AM   #2
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For Hi-Res stills, potentially (although I bet most people would not notice, and there are a lot worse brands out there than Hoya). For video, I doubt you'd see the difference at all.

I ALWAYS use a filter on all my lenses as I want to protect my expensive lens investment and I generally buy very good quality multicoated filters (e.g. B+W) as stills are important for me as well as video. Like lenses, I buy the best I can afford as I figure I'll only need to buy them once, with luck.

One of the downsides of filters is the extra (potentially) reflective surfaces to catch light/some flare etc. - but then I always shoot with hoods on to help reduce this (and this also provides a little more "accidental knock" protection to the front of the lens). Shoot video of your children at close quarters and you'll soon see what I mean!

One of the downsides of shooting without filters is that you can potentially scratch/damage the front of your lens making it totally useless from that point forward either while it's on the camera or by clumsily swapping lenses in the heat of the action. This is a risk I like to reduce. Also, some of the corporate environments I have to take my gear into are "less than ideal" for high quality optics/sometimes the risk of flying fragments etc. Also, anyone who shoots moving vehicles (and I sometimes do) also stands the risk of a small stone flying up and hitting the lens - it does happen as some have posted about this on here in the past!

I know which downside I personally prefer...but there are some who dislike any extra glass in front of their lenses for fear of degrading the image in any way.
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Old June 20th, 2010, 07:52 AM   #3
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Thanks Andy, very useful. I'm just struggling to get the image sharpness I'm after at the moment and trying to work out why. Sounds like I can cross this one off the list!
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Old June 20th, 2010, 09:39 AM   #4
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Tim, if you have flattened your video shooting menu, then the lack of contrast will make the image seem softer. Also if you are shooting wide open apertures for shallow depth of field, focus has to be spot on and also most lenses are at their softest wide open, maximum sharpness is obtained from f5.6 to f11.

I don't use UV filters.
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Old June 20th, 2010, 11:50 AM   #5
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Tim - you don't tell us what cameras you want to fit filters to. If it's a Canon 5D2 then have no hesitation in fitting filters, but listen to Andy - fit the best and then hood the lens/filter combo. Remember that the filter is now your lens's new front element, and as such its multi-coating should be the very best as this is where the most flare is generated.

If you're talking about fitting filters to a Sony V1, say, then beware. Norman's .'maximum sharpness is obtained from f5.6 to f11' most certainly doesn't apply to cameras that use tiny chips, and maximum aperture will be a lot sharper than f/11.

And remember, when you fit a filter to a video camera's zoom lens the slightest imperfection will be visible in any against the light shot at wide-angle. We're talking focal lengths in the order of 3mm, and getting both surfaces of the filter medically spotless is an impossibility.

tom.
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Old June 21st, 2010, 04:23 AM   #6
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Quote:
Originally Posted by Norman Pogson View Post
Tim, if you have flattened your video shooting menu, then the lack of contrast will make the image seem softer. Also if you are shooting wide open apertures for shallow depth of field, focus has to be spot on and also most lenses are at their softest wide open, maximum sharpness is obtained from f5.6 to f11.

I don't use UV filters.
Very interesting, thanks Norman. I think the video shooting meu could be the culprit. Followed advice rather blindly on this when I first purchased the camera but has meant I'm not getting the results I'm after. I'm looking for the 'sharpness' in low light situations like this video:


Hi Tom - All being done on the 7d :)
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Old June 21st, 2010, 08:22 AM   #7
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Nice film Tim. But you're worrying about filter losses when you're shooting with a full-frame-fisheye in a dance dungeon?? With rolling shutter flash frames that make me yell out? In such a scenario I tell you - anything goes. Loads of energy in your piece - loved it. Sharpness settings were the last thing on my mind.
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