Please read my previous post Chan.
Originally Posted by Chan Tran
The fact that when using the SBC like an reflective meter, but with the lumisphere set in the incident position, gives readings that match the E-P1, is just coincidence. It makes sense though because you say you need to set compensation to 4 and I believe that the SBC comp dial gives filter factor (not stops) so this means the meter will read 25% of the value that it would read with the compensation set to 1. The lumisphere is designed to give the same reading as if you were using reflective metering on an 18% gray card - in other words, when misused as a reflective meter, it should read about 18% of the real value. This is close enough to the 25% given by your exposure comp as to give an almost identical reading. I would not use the lumisphere for reflected light measurements though, since it will give you a 180% (hemispherical) field of view, which won't match your camera FOV (unless using a 180 degree fisheye!).
I'm not going to weigh in on the EP-1 as a light meter debate, but you might find Ctein's discussion of ISO useful. He's an experienced analog photographer and printer, as well as a digicam user. You can find it on TOP at http://theonlinephotographer.typepad...-isnt-iso.html.
Last edited by andrew.roos; 10-29-2012 at 11:08 AM. Click to view previous post history.
Light meters and sensors even in different makes and models of digital cameras give different readings at I.S.O 100 because the meter is designed for that particular models individual sensor.
1. I do not own an 18% grey card, but I want to own one now.
2. My understanding is that pointing the meter from the position of the camera at the subject is reflective; pointing the meter from the position of the subject back at the camera is incident
3. I made two additional comparision measurements this evening, but which I need to do over.
4. I have been using the exposure readings from the E-P1 to set the exposure on a Technika III for the past five (5) months. Using this methodology the exposures seemed reasonably close to me. That's the main reason I thought to compare the sbc with the E-P1.
5. From the manual, p. 12: "For example, assume that a filter with filter factor of 4x is being used which represents a change of 2 stops. By moving the index mark of the EF ring to a position opposite the number 4, the meter readings will automatically be compenstated for the 2 stop difference."
Last edited by noparking; 10-29-2012 at 09:23 PM. Click to view previous post history.
Reason: submited accidently the first time
Incident readings are done using the white dome on the meter, without it you're reading reflected light.
For incident readings, you would usually point the meter towards the camera, though sometimes toward the light you're looking to expose for. Otherwise, for reflected readings point it at the surface or scene you want to measure. The incident readings and reflective readings will (should) match if you're metering a greycard, or at least be within 1/2 stop or so.
What sort of result does the Gossen give you if you do an incident reading in full sun for 100 ISO? Should be in the ballpark of 1/100 sec @f/16...
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Pointing the meter from the position of the camera at the subject with the dome off is reflective; pointing the meter from the position of the subject back at the camera with the dome in front of the cell is incident.
Originally Posted by noparking
Your exposure problems might be due to the incorrect usage of the dome.
I had the opportunity to take test readings with the SBC using a subject (an 11 story office building) I originally photographed on 29-Jul-2012 @12:31 p.m. this past week around 11:15 a.m. I believe the light intensity was very close between the days. (In retrospect, the photo shot in July, which was taken at 1/60 sec @f/11, was over exposed. I ultimately reduced brightness -20 in PS to correct.) The sbc meter registered just under 1/125 sec @f/16 in both reflective (from camera/no diffuser) and incident modes (stood in the front of the building facing the direction of where the shot was taken using the spherical diffuser for the incident reading).
Originally Posted by bdial
So my thought is, if I had this meter on the day of the shot, I probably would have chosen a setting of 1/250 sec @f/11 (a difference of two f-stops) and the picture would not have been over exposed (but maybe slightly under exposed). I'm looking forward to giving the sbc a try at my next shoot.
Thanks all for the feedback and links regarding ISO. It has been enlightening.
Aim your EP1 at an 18% grey card that fills the view, and note the reading. Now, in the same light, aim your Gossen meter in reflected metering mode at the same grey card and note its reading. Now, in the same light, aim the incident light hemisphere of the Gossen meter toward the camera lens position, and note its reading. If the three are not within about 0.66EV of each other, one of the meters (likely the Gossen) is in need of calibration.
The 'digital calibration' vs. 'film calibration' is a bunch of hooey!!! I can aim a Minolta one-degree flashmeter at a grey card, I can aim my Canon digital camera at a grey card, I can aim my Olympus OM-1 at the same grey card, and they all agree with my Minolta Autometer Vf in incident mode. I just did it, to make sure I am not making false claims!
Last edited by wiltw; 11-03-2012 at 02:37 PM. Click to view previous post history.
I occasionally use a digital camera for "spot" metering when using film (as I don't own a spot meter) ...
Originally Posted by wiltw
I've read a few times (on APUG) that the metering of digital cameras and that of handheld meters is different and incompatible. The implication is that using a digital camera to meter for film will inevitably produce exposure errors. Presumably, therefore, using a handheld meter with a digital camera will inevitably also produce exposure errors?
Yet there are dozens of models of meter still being made and sold ... are they only being used with film ?
I've looked at a few user manuals for current handheld meters, and none of them have said that they cannot be used with digital cameras ...
I agree with you there. Another thing I have found is that, I have a Nikon Coolpix 5000 and its meter isn't very good. If I use my F5 on matrix and use the reading of the F5 and set it on the Coolpix I would have good exposure but if the F5 produces bad exposure on film.
Originally Posted by pdeeh