I was talking with Brent D the other day about how he meters for shots he is exposing with his ND Grad filters and we both thought it might be a good idea to create a thread out here to discuss this for everybody's benefit.
Personally I do find it somewhat confusing and a little bit of voodoo to come up with a sound repeatable process for coming up with a solid exposure reading.
So if you have a definite process and/or suggestions please let us all know.
Thanks.
RichieV
Posted by Rene Pirolt on August 27, 2007 at 11:49 AM
Rich – I know you use a spot meter…so here is how I do it.
For Hard Edge filters, if I meter the scene in the area NOT covered by the ND portion of the filter, I increase my exposure to 1/3 to 2/3 of a stop,
If I meter the scene in the area covered by the ND portion of the filter, I increase my exposure by the filter factor and subtract 1/3 to 2/3 of a stop. For example on a 2 stop Hard Edge ND Grad, I increase the exposure by 1 1/3 to 1 2/3 of a stop.
If I use a Soft Edge filter, I adjust by a whole stop.
This method has worked very well for me in the past.
Posted by Kalin Wilson on August 27, 2007 at 11:54 AM
I found myself struggling with this up at Missouri Lakes in July. I hadn't messed with filters on the LF yet but really needed ND Grads with the early alpenglow.
What I did, and it seemed to work OK, was choose the grad that would compress the zone range to 4-5 zones and use the exposure for the narrower range. For instance, if the metered range was 9ev to 16ev (7 stops), I chose a 2 stop GND placing it over the brightest highlights, bringing them down to 14ev. Then I set my exposure using my handy-dandy zone dial placing 9ev in zone III.
This method is simpler for me than using filter factors and all that. Maybe it's essentially the same. I metered through my GND to prove to myself that it really was a 2 stop cut at the top of the filter. I also metered through the filter across the scene to verify the exposure that I got from the dial and everything seemed to jive.
For the sunrise shots that I got from that shoot I think I got pretty good exposures for the range of light. If anything, they might have been 1/3 to 1/2 stop underexposed in the shadows but the highlights were on.
I'm really interested to hear what others do, especially Rick. He seems to do a lot of combining of GNDs to great effect. Great thread!
Posted by Tony Bouchard on August 27, 2007 at 12:43 PM
I meter along the line where I'll locate the bottom edge of the grad and increase the exposure 1 stop for a 2-stop soft grad & 2 stops for a 3-stop soft grad. For example, if the brightest part of the scene along the bottom edge of the grad is clear sky at sunrise, I'll increase exposure 3 stops from the meter reading if using a 2-stop soft grad.
Posted by Doug Andrews on August 27, 2007 at 12:45 PM
Well regardless of whether I'm using a GND or not, I always make a point of heavily weighting my exposure on retaining detail in my highlights. I really don't like burned out highlights. I'd rather my shadows lose all detail and go pure black before having my highlights lost. When using a GND, I always use spot metering. Well thats not exactly true. I'll use the matrix meter in my D200 to get me in the general ball park. From there I switch to spot metering and use the different AF points which can be used as selectable spot meters to determine what the brightest and darkest parts of the composition are and the range of eV. Based on that I decide if a 2-stop or 3-stop GND is needed. Sometimes I'd need a 5-stop GND and then I just don't take the shot. I place the GND is the holder and align it. Then retake spot meter readings of the scene using the different AF points to confirm the eV range was decreased by the strength of the GND and tweak the exposure so that the brightest highlight still has detail in it. From here I pretty much let everything else fall where it may. This technique seems to work for me the majority of the time. Maybe not the best way of using a GND. Hopefully I can pick up some better ways in this thread.
Posted by Jack Brauer on August 27, 2007 at 2:09 PM
I just use my normal method of averaging the EV readings throughout the scene, keeping in mind the subtraction involved by the grad. Pretty simple I think.
I found it much more confusing to use grads on an SLR (without a handheld lightmeter with EV readings). In fact I never really figured it out, and have since sold all my SLR gear anyways.
Posted by Paul Beiser on August 27, 2007 at 2:27 PM
I look at the histogram on my DSLR, and change the exposure accordingly
I have two general methods for LF depending on whether I'm using the GND to control very hot highlights, or if I'm using it to bring the sunlit and shaded areas of a sunrise or sunset closer together.
For the highlights like very bright clouds or snow fields, I spot meter the highlights in the scene that fall in the filtered area. I place that value at zone 7 or 7.5 depending on what film I'm shooting. I take the corresponding exposure settings and add 2 stops or 3 stops depending on the filter being used; I might back off a 1/3 or 2/3 of a stop if the metered area is closer to the grad line. Then, I take my final exposure settings and compare to meter readings from the unfiltered areas just to make sure that those won't get blown.
For sunrise/sunset scenes where there are not specific, prominent highlights, I use Jack's approach and try to keep the darker foreground elements at about Zone 3.5 to 4.
Kalin mentioned my use of grads, which gets a little more creative when using the D2X because I can look at the result immediately and adjust as necessary (I rarely meter with the DSLR; looking at the histogram is much faster and more reliable for me). I like being able to put a 3 stop on the top and invert a 2 stop from the bottom and have them meet/overlap in the middle - things like that. I wish I could the same things with grads on the LF - and I've tried - but the results are totally unpredictable unless you have a polaroid back and can afford trial and error with a few polaroid sheets. Otherwise, having the filter placement off by 1/4" - 1/2" can create a really messy image.
Posted by Mel Ladewig on August 27, 2007 at 7:28 PM
On a DSLR, I meter in evaluative mode and click. Check the histogram, preview the image on the LCD and adjust EC as needed.
I'm still learning my LF camera, but for now, I'm matching up the focal length from my DSLR, placing the same GND on both and taking the evaluative meter reading from the SLR. So far, so good. I got two shots developed a couple weeks back and both were focused correctly and exposed correctly. Here's to $100 dollar LF cameras
Discussion
8 repliesPersonally I do find it somewhat confusing and a little bit of voodoo to come up with a sound repeatable process for coming up with a solid exposure reading.
So if you have a definite process and/or suggestions please let us all know.
Thanks.
RichieV
For Hard Edge filters, if I meter the scene in the area NOT covered by the ND portion of the filter, I increase my exposure to 1/3 to 2/3 of a stop,
If I meter the scene in the area covered by the ND portion of the filter, I increase my exposure by the filter factor and subtract 1/3 to 2/3 of a stop. For example on a 2 stop Hard Edge ND Grad, I increase the exposure by 1 1/3 to 1 2/3 of a stop.
If I use a Soft Edge filter, I adjust by a whole stop.
This method has worked very well for me in the past.
What I did, and it seemed to work OK, was choose the grad that would compress the zone range to 4-5 zones and use the exposure for the narrower range. For instance, if the metered range was 9ev to 16ev (7 stops), I chose a 2 stop GND placing it over the brightest highlights, bringing them down to 14ev. Then I set my exposure using my handy-dandy zone dial placing 9ev in zone III.
This method is simpler for me than using filter factors and all that. Maybe it's essentially the same. I metered through my GND to prove to myself that it really was a 2 stop cut at the top of the filter. I also metered through the filter across the scene to verify the exposure that I got from the dial and everything seemed to jive.
For the sunrise shots that I got from that shoot I think I got pretty good exposures for the range of light. If anything, they might have been 1/3 to 1/2 stop underexposed in the shadows but the highlights were on.
I'm really interested to hear what others do, especially Rick. He seems to do a lot of combining of GNDs to great effect. Great thread!
I found it much more confusing to use grads on an SLR (without a handheld lightmeter with EV readings). In fact I never really figured it out, and have since sold all my SLR gear anyways.
For the highlights like very bright clouds or snow fields, I spot meter the highlights in the scene that fall in the filtered area. I place that value at zone 7 or 7.5 depending on what film I'm shooting. I take the corresponding exposure settings and add 2 stops or 3 stops depending on the filter being used; I might back off a 1/3 or 2/3 of a stop if the metered area is closer to the grad line. Then, I take my final exposure settings and compare to meter readings from the unfiltered areas just to make sure that those won't get blown.
For sunrise/sunset scenes where there are not specific, prominent highlights, I use Jack's approach and try to keep the darker foreground elements at about Zone 3.5 to 4.
Kalin mentioned my use of grads, which gets a little more creative when using the D2X because I can look at the result immediately and adjust as necessary (I rarely meter with the DSLR; looking at the histogram is much faster and more reliable for me). I like being able to put a 3 stop on the top and invert a 2 stop from the bottom and have them meet/overlap in the middle - things like that. I wish I could the same things with grads on the LF - and I've tried - but the results are totally unpredictable unless you have a polaroid back and can afford trial and error with a few polaroid sheets. Otherwise, having the filter placement off by 1/4" - 1/2" can create a really messy image.
I'm still learning my LF camera, but for now, I'm matching up the focal length from my DSLR, placing the same GND on both and taking the evaluative meter reading from the SLR. So far, so good. I got two shots developed a couple weeks back and both were focused correctly and exposed correctly.
Mel-