len10@ihuxw.UUCP (06/10/83)
What are the practical differences between 1A skylight and UV filters? Len Dombrowski BTL - Naperville, ILL.
brad@sdcrdcf.UUCP (06/16/83)
In reference to the question about Skylight 1A and UV filters: Both the Skylight 1A and UV filter some blue-violet-ultraviolet. The UV is specifically used for the Ultra-Violet, while the 1A also 'warms' the scene somewhat. If you look closely at each, the 1A is 'pink', while the UV is visibly clear. (It wouldn't be if you could see UV) The reason for filtering UV is because the film in your camera is not sensative to the same range as your eye, it can 'see' the UV, which will make your photographs come out bluer than normal. This is normally not a problem, but can be, especially at midday and at high altitudes. In these cases, sunlight is considered 'cool', because it consists of a high percentage of 'blue' light, as opposed to morning, evening or low altitudes where the light has less blue and more 'red', thus being 'warmer'. They are both also used as lens protectors, since they pass what you see relatively unchanged (except 1A is slightly redder) and are much cheaper than a lens. I don't want the warming of a 1A usually, so all my lenses are fronted with a UV. The distortion of a good quality filter is usually negligible. Brad Spear sdcrdcf!brad
dkw@homxb.UUCP (D.WOMBOUGH) (12/11/85)
Can anyone recomend a filter that will correct the yellow tint that is produced when a photo is taken with indoor lighting. Also is there a filter that will allow me to use high speed film (iso 1000) outside in brite sun light without shooting at 1/1000 sec at f22 ? Thanks Dennis Wombough
howard@sfmag.UUCP (H.M.Moskovitz) (12/13/85)
> Can anyone recomend a filter that will correct the yellow tint > that is produced when a photo is taken with indoor lighting. > Also is there a filter that will allow me to use high speed film > (iso 1000) outside in brite sun light without shooting at 1/1000 sec > at f22 ? > > > Thanks > Dennis Wombough The reason you get a yellow tint indoors is that you are using a film that is balanced for the color temperature of sunlight as opposed to lightbulbs (also known as tungsten light). To use that film indoors with incandescent lighting you need a # 82B blue filter. To shoot under flourescent lighting you need a light pink filter (53??). Another solution to the problem is to use a film that is color balanced for use with tungsten lighting. Kodak makes both print and slide films like that as well as Fuji, 3M, and Agfa. The 3M tungsten slide film is ASA 640! As far as shooting ASA 1000 in bright sun, it better not to. Use a slower film that will not need such small apertures and at the same time will give much better resolution (less grain) and color saturation. I reccomend ASA 200 as an all-around outdoor film or ASA400 for cloudier low-light days. If you must use a filter to reduce light, you want a Neutral Density filter. This is a grey filter that reduces light by a certain number of f-stops without affecting color balance or resolution. They come in different 'strengths'. A 2x filter reduces 1 f-stop while an 8x reduces 4. These are very useful for shooting into the sun in the afternoon. They can also be stacked to have an additive effect (i.e., a 2x + a 2x = a 4x). -- --------------------------------------------------------------------- Howard Moskovitz AT&T Info. Systems attunix!howard
mfs@mhuxr.UUCP (Damballah Wedo) (12/13/85)
> Dennis Wombough: > Can anyone recomend a filter that will correct the yellow tint > that is produced when a photo is taken with indoor lighting. The orange cast is due to the color of the light itself, which has much less blue than sunlight. To emphasize what blue there is, try using 80A or 80B blue filters. I have found that they almost-but-not-quite correct tungsten light orange casting. What cast is left tends to add golden hues to human skin and generally deepens earth tones, which is pleasant. Of course, you can avoid the problem entirely, by using black-and-white film. > Also is there a filter that will allow me to use high speed film > (iso 1000) outside in brite sun light without shooting at 1/1000 sec > at f22 ? There are various neutral (e.g. gray) filters, that do not affect the color of the light reaching the film, but diminish its intensity. You can also try shooting with slower film (finer grain). -- Marcel-Franck Simon ihnp4!{mhuxr, hl3b5b}!mfs " Krik." "Krak." " Kapite`n anba kabann." "Vaz."
darryl@ism780c.UUCP (Darryl Richman) (12/13/85)
In article <1002@homxb.UUCP> dkw@homxb.UUCP (D.WOMBOUGH) writes: >Also is there a filter that will allow me to use high speed film >(iso 1000) outside in brite sun light without shooting at 1/1000 sec >at f22 ? You can buy neutral density filters that will decrease the light entering by 1, 2, and 3 f stops. I've also heard of using a polarizing filter, but that can do weird things to the sky. --Darryl Richman, INTERACTIVE Systems Corp. ...!cca!ima!ism780!darryl The views expressed above are my opinions only.
kemasa@sdcc13.UUCP (kemasa) (12/13/85)
In article <1002@homxb.UUCP> dkw@homxb.UUCP (D.WOMBOUGH) writes: >Can anyone recomend a filter that will correct the yellow tint >that is produced when a photo is taken with indoor lighting. I can't remember the filter number, but if you look at the paper that comes with the film, now on the inside of the box on Kodak film it will say. It is a blue filter I think an 81a. Also the is a filter for tungsten (sp?) films to be able to shoot outdoors. Any camera store will be able to tell you want the filter is. You could just use a blue filter, but I would suggest using the correct one or using a flash. >Also is there a filter that will allow me to use high speed film >(iso 1000) outside in brite sun light without shooting at 1/1000 sec >at f22 ? > Dennis Wombough Neutral Density filters do this job and come in several densities, it is also useful if you want a more limited depth of field with normal films and/or slower shutter speeds. There are filter to do just about anything, photo magazines sometimes have articles on different filters. As a side note I hope you and everyone reading this uses a filter all the time to protect the lens, like a UV filter or whatever. I don't know if this has been brought up before or not, but it can really save your lens. Kemasa.
ron@brl-sem.ARPA (Ron Natalie <ron>) (12/14/85)
> Can anyone recomend a filter that will correct the yellow tint > that is produced when a photo is taken with indoor lighting. > Also is there a filter that will allow me to use high speed film > (iso 1000) outside in brite sun light without shooting at 1/1000 sec > at f22 ? > Go to your camera store and ask, I can never remember the numbers. The common one (80A?) is for tungsten photo floods. As I recall this is not quite the same as normal room lighting, so perhaps they have a better one. I typically end up buying one to make my tungsten film good with my flash/daylight (82?) and shooting tungsten film indoors. I usually need the extra stop or two that the filter takes when shooting by ambient tungsten, and need it less in daylight or with flash. Florescent and various vapour lamps are a different story, but you said yellow, so I'll assume you're problem is tungsten. To just cut down on light, use a Neutral Density (ND1, ND2) filter. This appears just to be a grey hunk of glass. ND5 is recommended for taking direct pictures of the sun (I shot some series of a solar eclipse a few years ago). -Ron
thoth@tellab3.UUCP (Marcus Hall) (12/16/85)
References: Since the subject has come up, what books are reccomended for learning about filter usage? Also, when using a filter with a through the lense meter, is it necessary to adjust the exposure by the filter's f-stop rating? Does altering the spectrum of light being metered confuse the metering system? Please Mail responses! Thanks, marcus hall ..!ihnp4!tellab1!tellab2!thoth
howard@sfmag.UUCP (H.M.Moskovitz) (12/16/85)
> > Since the subject has come up, what books are reccomended for learning > about filter usage? > > Also, when using a filter with a through the lense meter, is it necessary > to adjust the exposure by the filter's f-stop rating? Does altering the > spectrum of light being metered confuse the metering system? > Since the TTL metering system measures light intensity as it hits the film plane, adding filters is compensated accordingly. Metering systems do not know anything about color so this has no effect. -- --------------------------------------------------------------------- Howard Moskovitz AT&T Info. Systems attunix!howard
kanner@tymix.UUCP (Herb Kanner) (12/18/85)
In article <394@sdcc13.UUCP> kemasa@sdcc13.UUCP (kemasa) writes: > Neutral Density filters do this job and come in several densities, >it is also useful if you want a more limited depth of field with normal >films and/or slower shutter speeds. There are filter to do just about >anything, photo magazines sometimes have articles on different filters. >As a side note I hope you and everyone reading this uses a filter all >the time to protect the lens, like a UV filter or whatever. I don't know >if this has been brought up before or not, but it can really save your >lens. > > Kemasa. The notion of always protecting a lens with a low-effect filter, such as a UV filter, is considered very controversial among professional photographers. The reason is that any extra glass-to air interface, even with modern coatings, reduces image contrast measurably. I have read articles or chapters in books in which it is recommended to use the UV filter either when it is needed, or when one is in a hostile environment, such as the sea shore. Personally, I have compromised. I do not keep a filter in simple lenses, which can be replaced for between $50 and $100. I do keep a filter in zoom lenses and vari-focal lenses. -- Herb Kanner Tymnet, Inc. ...!hplabs!oliveb!tymix!kanner
amr@rti-sel.UUCP (Alan Roberts) (12/18/85)
In article <814@sfmag.UUCP> howard@sfmag.UUCP (H.M.Moskovitz) writes: > . . . >Since the TTL metering system measures light intensity as it hits >the film plane, adding filters is compensated accordingly. Metering >systems do not know anything about color so this has no effect. > . . . True enough (at least in my experience, which doesn't include any critical scientific photography or the like), but one type of filter which CAN trip up the TTL metering of SOME cameras is a polarizer. It doesn't happen to all cameras (I think it is related to use of a half-silvered mirror to direct light to the metering sensors). I also think a summer issue of some mag. (Peterson's ?) had a fair list of which 35mm bodies were sensitive to the problem and which were immune. You can also purchase a "circular" polarizing filter which doesn't cause the problem (they are more expensive). Cheers, Alan Roberts Research Triangle Institute (decvax!mcnc!rti-sel!amr) -- Cheers, Alan Roberts Research Triangle Institute (decvax!mcnc!rti-sel!amr)
kanner@tymix.UUCP (Herb Kanner) (12/19/85)
In article <814@sfmag.UUCP> howard@sfmag.UUCP (H.M.Moskovitz) writes: >> >> Since the subject has come up, what books are reccomended for learning >> about filter usage? >> >> Also, when using a filter with a through the lense meter, is it necessary >> to adjust the exposure by the filter's f-stop rating? Does altering the >> spectrum of light being metered confuse the metering system? >> > >Since the TTL metering system measures light intensity as it hits >the film plane, adding filters is compensated accordingly. Metering >systems do not know anything about color so this has no effect. > >-- > > >--------------------------------------------------------------------- > Howard Moskovitz > AT&T Info. Systems > attunix!howard Not strictly true. True for most practical purposes. If the spectral response of the meter differs sufficiently from that of the film, there will be a net change in effective film exposure when the filter is used. This can be checked if the film and/or filter manufacturer has supplied a filter factor and if the camera has read-outs telling what it is doing. See what the readings are before and after attaching the filter and see if the reading change is consistent with the published filter factor. I certainly remember that for certain really extreme filters, e.g. red, meant to be used with B & W film, that the factor varied quite a bit from one film to another. In fact, you sure as hell wouldn't use a red filter with orthochromatic film :-) -- Herb Kanner Tymnet, Inc. ...!hplabs!oliveb!tymix!kanner