Measuring light angle - 25 or 52 degrees?

[geoffgp]

<p>I've now decided to buy a digital light meter and am looking at either a Gossen Digipro F or a Sekonic L358. I prefer the size of the Gossen but I'm not sure which would be the best to get in terms of measured angle of received light in reflected mode (the mode I prefer). The Gossen spec is 25 degrees while the Sekonic is 52 degrees. I tend to use lenses in the 35mm to 85mm range mostly. But I do use 20mm and even 180mm. Mostly outdoor.<br />Thanks Geoff</p>

[Matt Laur]

<p>Are you talking about using the meter with a spot attachment?</p>

[geoffgp]

<p>Hi Matt, Didn't really want to buy a spot attachment as well. So the answers probably no.</p>

[Matt Laur]

<p>So if you're just going to use it as a general incident meter, I think either meter is going to suit you just fine. It might make more sense to focus on other ergonomics and features. Any chance you'll be using it as a flash meter? Need to measure accumulated flash pulses? Need to have the meter trigger some Pocket Wizards (like the Sekonic, optionally, can)? That stuff is where the practical differences are, as long as you're not going for narrow spot metering. You're just going to hold that meter's sensor dome near your subject, pointing back towards the camera position, and both meters will do a great job. I'm partial to the L358 because I use PWs for flash triggering, but it's really a matter of taste. It's a very nice meter.</p>

[geoffgp]

<p>No, I don't intend to use it as a flash meter really. But I really intended to use it in reflected mode for street and mid to long distance landscapes. And just wondered if an angle of 25 degrees was a bit narrow for that with a 35/50 /85 attached.</p>

[Alan Marcus]

<p >Light meters are calibrated to read a medium gray surface. This is a surface with a neutral color, one that reflects away 18% of the light that plays on it. This tone stems from Kodak engineers suggesting the use of the yellow Kodak film box as a suitable target to be use with newly introduced electric light meters in the 1930's. Some time latter, the gray cards replaced the yellow box top. The gray card method of exposure determination was popularized in the 1940's by Ansel Adams, a prominent photographer and his friend Fred Archer an editor of a popular photo magazine. Since that time, the 18% target has become engrained as a test target used to calibrate film, photo paper and most light measuring instruments. </p>

<p >The initial use of the light meter was to measure the reflected light from the subject. This method has its pitfalls because the optics of the meter tends to average (integrate) the scene. Many scenes do not fit an average because of unequal distribution of bright and dim objects. Many meter reading techniques abound. Often the meter is brought closeup to the subject so that the reading is specific to certain areas. Some meters are coupled with telescope like optics that narrow the reading to just a spot on the subject. This allows specific area measurements from afar. </p>

<p >As the meter evolved, it became popular to measure the light just before it played on the subject. In this technique, the meter is held close to the subject and pointed back at the camera. The optics of the meter are modify with an entry sphere, a white translucent dome that captures a broad angle of light just before it hits the subject. This method gives the same reading as a close-up or spot reading of a gray card read by reflected light. The method is call incident from old French falling upon. </p>

<p >Because of the pitfalls of meter reading, modern in-camera meters are augmented by chip logic. The chip logic takes into account the distribution of lightness and darkness of the subject. We sometimes call this weighted average. The in-camera meter is hard to best. </p>

<p >As to the handheld meter: It makes little difference as to the angle of light acceptance. No matter which values your meter will use, you must apply your experiences and wisdom. Do not let the angle of entry be your deciding factor. </p>

[barry_kenstler1]

<p>Geoff,<br>

If you're not going to measure flash and expect to use the meter in reflected mode for the most part, I'd suggest scaling back a little. You might be happier with the smaller Sekonic L308 S meter. The diffuser slides to the side for reflective readings so you don't have the problem of losing or misplacing the hemisphere. If you want the narrower acceptance angle of the Gossen and don't mind purchasing used, look for the original Luna Pro Digital (non-F) version which has a narrow acceptance angle, a captive sliding hemisphere, and is easy to use. I had mine swiped by a homeless fellow and still miss it. <br>

By the way, I prefer the narrower acceptance angles for doing more selective readings in the scene. I like to take my readings of portions of the scene that should reproduce as middle tones. Just pointing the meter straight ahead, particularly if there is a large portion of the sky in view, often leads to underexposure. The acceptance angle is really not that important. You can usually adjust your technique to fit the meter.</p>

[geoffgp]

<p>Barry, <br>

Thanks for the response. I'll check out both of those. If the Gossen has aperture priority as well, even better. I don't really want to spend any more than I need to! </p>

[david_henderson]

<p>The OP appears to be trying to relate the angle of acceptance of a meter to the field of view of the lenses he uses. Can't really do that because we don't know what camera he uses (35mm/full frame? crop frame?) and in any case the meter's angle of acceptance will be circular whilst the field of view will be rectangular, varying in size with lens focal length and varying also according to whether the camera is horizontal or vertical. So whilst saying on the one hand that a 25 degree angle of acceptance is broadly equivalent to the diagonal fov of a 35mm lens of 100mm and a 52 degree acceptance is the broad equivalent of the diagonal fov of a 45mm lens for a 35mm, I think on the other hand that its a pretty irrelevant concept. </p>

<p>The big issue for me with wide angle (ie non spot) reflected meters is that its tough to work out where the reading is being taken from and just why a tiny hand movement can result in significant changes to the reading given. I suspect that a large majority of these meters are used primarily in incident mode where the concept of "where is this reading coming from" is less relevent. If it helps, 52 degrees is a little more than half the distance between the tips of your toes and the sky right over your head. IMO the inability to see and adjust with any sort of accuracy the area the reading originates from is a major weakness of this form of metering, and that with a critical medium such as slides and some digital that this factor is significant. It means to me at least that a decent ttl metering system is likely to give more useful results than a wide receptor handheld meter used in reflective mode. </p>

<p>If you really want to buy a meter like these to use in reflected mode then, after having had poor experience myself with a 358 I'd suggest the Gossen simply because its easier to get a reading that you know is "all sky" or "all foreground" with a narrower acceptance. But that's only making the best of a sub-optimal metering regime IMO.</p>

[david_henderson]

<p>Sorry -meant to say the 52 degrees is a little over <strong><em>a quarter </em></strong>of the distance between the tip of your toes and the sky right over your head.</p>

[geoffgp]

<p>I suppose the Nikon F will just have to go out with his little brother the D700!<br>

The OP</p>

[wayne_f1]

<p>The Sekonic L-308 is spec'd with a 40 degree angle for reflected. That is what I have, and I like it, and would replace with same thing if necessary, but I use it for flash (incident). Simple to use and more than plenty. However outdoors, it has no Aperture Preferred setting, it is only Shutter Preferred. Which is perfect for flash, but is awkward to me outdoors.</p>

[barry_kenstler1]

<p>Geoff,<br>

The Gossen Luna Pro Digital and the subsequent Digital F ( with Flash measurement ) are switchable between aperture (F) and shutter (T) priority. They are holding their value well on the used market. I saw a Digital non-F at B&H for $150, which is just short of what I paid for mine new. The only complaint I have with the modern Gossen meters is battery life. They eat batteries faster than other meters in my experience. Not many people take the Polaris meters seriously, but I have the original plain flash version and it's been great to me. It's been through hell and back and is still accurate after 15 years of use. Not the best for balancing flash and ambient, and like the Sekonic L308 shutter priority only, but I just love it. Older Minolta meters can be good too if you are considering going the used route. <br>

Barry</p>

[geoffgp]

<p>Wayne, I think I would find it awkward as well. Obviously you can work with shutter priority but it slows it all down especially for walking around type stuff. <br>

Barry, The Luna Pro Digital is called the Sixtomat Digital in the UK, and is retailing new for more than the F! Like you say used ones are not much less. I would buy used but I don't think it makes much sense given that. I definately want digital for the speed and clarity of the reading and for the portability. I can see myself spending more and going for a new Digipro F. It hurts though to pay the same for a plastic meter as a mint Nikon F, however important the meters job! I will check out those older Minoltas though.<br>

Thanks Geoff</p>