R-D1 Exposure Question

[Jim Watts]

There have been a number of previous threads on the R-D1's metering characteristics, for example

http://www.rangefinderforum.com/forums/showthread.php?t=22545&highlight=meter+under

http://www.rangefinderforum.com/forums/showthread.php?t=5143&highlight=meter+under

In general the consensus is that the R-D1 under exposes to protect the highlights by 2/3 EV, which in most cases is my finding and the correction I set as standard.

The metering characteristics of nearly all external light meters will be set for the characteristic curve of film (usually slide) and not for a digital senor which will be more linear and therefore will probably only be applicable/agree in the midrange (Zone V).

 

[sonwolf]

The R-D1's ISO ratings are inflated. The image sensor's light sensitivity does not equal its ISO setting. I have shot a Color Checker chart with my R-D1 and Canon DSLR with matching exposures and the R-D1 consistently produces darker results across the whole exposure range. Assuming the scene is not dominated by light or dark tones and the highlights are not blindingly bright, adding +1/2 to +2/3 EV will produce a better exposure on the R-D1. In Tungsten light, the sensor's light sensitivity degrades further. An adjustment of +2/3 to +1 1/3 EV helps compensate.

 

[MCTuomey]

very useful responses! thanks, all. it's the sensor, not the meter, apparently.

i'll be using various EC settings as i work more with the camera to help compensate for the optimistic ISO rating.

 

[pphuang]

I'm hampered or helped (not sure which) by several years of digi sportshooting, so i'm mindful of the relation between underexposure and digital noise. My sports bodies are often semi-permanently EC'd +1/2 or more to avoid noise and reduce facial shadows.

I need to lose that habit, i guess, and think out of *my* box with the R-D1. I'll play around with exposures and see what I can learn.

I just wanted to emphasize this point one more time. At higher ISOs, you get noisier files, so if you underexpose and then adjust in post-processing, it really brings out the digital noise, especially in the shadows. In general, you want to keep you histo off the left side both to reduce this noise problem in post processing, and also to maintain as much shadow detail as possible. This is also why most are recommending +EC to compensate for the tendency of the R-D1 to underexpose, although this increases the risk of blow-out, which is un-recoverable in digital (unless you shoot with an S5, but that's a topic for another day 😉 )

However, let me give you another technique that you should consider. As you know, there is very little shadow noise when you shoot at lower ISOs. So, although it may seem counter-intuitive, it actually works quite well to intentionally UNDEREXPOSE your photos using a low ISO setting (200-400), which lets you keep the shutter speed at a reasonable range, especially with slower lenses. There is very little digital noise it the file, so exposure adjustments can me made in post without the noise problems, and you will be amazed at how much shadow detail is still available if you shoot in raw.

Here's an example. This is a scene with a pretty wide dynamic range shot with an R-D1s. This was shot in RAW mode with an ISO setting of 400 and EV set at -0.7. I'm pretty sure that the aperture was at 2.8, and the underexposure allowed me to keep my shutter speed at 1/125, which is quite good for a dark, indoor scene.

This is the original file without any post processing:

And the same image after adjustment in PS:

You can see that the lamp flair in the upper right corner is well exposed without blowout, and yet there is a tremendous amount of shadow detail that can be teased out without much difficulty. You can also see that the overall noise level remains very low.

I could have just as easily shot this at 1600 with a normal EV, but I have found that this tends to give me much noisier files.

Give it a try! 😀

 

[MCTuomey]

Paul, very interesting approach and successful judging from the pic, quite contrary to my experience shooting in dark gyms, HS fields at night, etc. What result do you think you'd have obtained with, say, ISO 1600 and +1 to +2 stops of EC, rather than just zero EC at ISO 1600?

 

[pphuang]

Mike, if the lighting is pretty good, then shooting at 1600 and +1 or +2 can give you pretty nice files as well, but the lighting has be to good enough to give you reasonably fast shutter speeds. Unfortunately, this will increase the risk of blow-outs if you have a high contrast scene. In dark lighting, +1 or +2 gives you very slow shutter speeds which may be a problem depending on your subject. If you are shooting with a relatively slow lens, this becomes even more of a problem.

Personally, I find in low light situations that shooting low iso and underexposing gives me more consistent results in a wide variety of conditions, and also allows me to use some of my slower lenses in poor light...

 

[MCTuomey]

paul, i look forward to trying your low iso/underexpose suggestion, especially since i'm a fan of compact "slow" lenses, thanks.

 

[sonwolf]

Paul,

What were the PS settings you applied to the under exposed image to produce the final result? I am especially interested if the majority of the correction happened in ACR or Photoshop.

 

[pphuang]

Paul,

What were the PS settings you applied to the under exposed image to produce the final result? I am especially interested if the majority of the correction happened in ACR or Photoshop.

Each shot is different, so the settings vary from photo to photo. Also, if you under-expose too much, the colors will look muddy. This usually happens if there is a lot of backlighting, so you have to compensate for that. I make all the level adjustment in ACR or Lightroom, which have similar controls that are much more intuitive than using curves in PS.

 

[sonwolf]

Paul,

I realize each image requires different corrections, but how much exposure boost did you give this image? Did you apply significant noise reduction?

Your approach completely contradicts classical Raw exposure technique. Anyone who thinks outside the box, always interests me.

 

[pphuang]

Paul,

I realize each image requires different corrections, but how much exposure boost did you give this image? Did you apply significant noise reduction?

As stated by Tokek, its a useful technique that has been mentioned by others in the past. It allows you to get around some common photographic problems and can work very well, but it is no magic bullet, and if you underexpose too much, the results can look awful 😀

You will have to boost at least the amount that you underexpose, which makes sense if you think about it. It is the same concept as push processing with film - you underexpose your photo and then overdevelop the negatives. In this instance, you are taking advantage of the low noise characteristics of the sensor at lower iso, and the amount of lattitude in the shadows provided by the sensor and raw.

As for the photo in question, here are the setting from ACR:

Exposure +1.2
Recovery 61
Fill Light 16
Blacks 0
Brightness +84
Contrast +20

Highlight -25
Light +1
Darks -18
Shadows +2

The camera was set at iso 400 with EV set at -0.7

Some of the adjustments seem a little redundant, but if you are familiar with the menu layout in ACR, I try to get in the general ballpark with the first set of controls, and then fine tune with the second second set of controls, which is why it looks like I went up with recovery, but then down with highlights. This is just my particular work-flow, I'm sure that there are many ways to get the same results.

I did a little sharpening in PS, but no noise reduction was applied. However, you could add noise reduction if you want even smoother looking files, which is obviously a matter of taste.

Hope this helps...

 

[Rapha]

My R-D1 tends to underexpose about one stop just with a CV 21/4. The metering with my CV 40/1.4 is just excellent, so I'm a bit confused about that. Could someone explain me why is this happening?. Thanks.

 

[sonwolf]

Paul, thank you for posting the image’s ACR settings. I see your correction uses the Exposure slider to entirely compensate for the exposure deficit, combined with very aggressive highlight control and a moderate adjustment of midtones and shadows.

 

[LCT]

My R-D1 tends to underexpose about one stop just with a CV 21/4. The metering with my CV 40/1.4 is just excellent, so I'm a bit confused about that. Could someone explain me why is this happening?...

I would not say underexposition personally but the sensor receives less light due to light fall off. Look at your pics before vignetting correction, they can be quite dark in the corners. But the center remains well exposed, in my experience at least.
BTW whatever lens i use, i'm used to choose -1 EV with contrasty subjects. Works fine generally.

 

[sirius]

Thanks! This is a very interesting thread. I appreciate you sharing that advice Paul. It's really helpful. I can't wait to try that 200-400 ISO trick.

One thing to note is that digging detail from a very dark file can seem to emphasize the magenta cast. I think this file was 1600 ISO. It was not so purple in real life.

cheers all!

 

[pphuang]

One thing to note is that digging detail from a very dark file can seem to emphasize the magenta cast. I think this file was 1600 ISO. It was not so purple in real life.

Sirius, were the roof and the car black? Like the M8, the R-D1 also suffers from the magenta problem when shooting dark objects, although from what I have read, it is not as severe as the M8, and I personally never shoot with an IR filter. You can get some funny color casts when underexposing, but I'm never sure if its the technique or the low, mixed lighting that's the culprit. Its pretty easy to correct the white balance in raw using ACR, so I don't find it to be a big problem...