question: Exposure 'best practices' a7II --coming from a Pentax digital body

[gcristia]

Hello all

 

This is my first post here at the forum. Allow me to provide some background.  I think there may be some previous/concurrent pentax users out there ( this forum post was like a breath of fresh air due to some of the "issues" I have been having with a7II  This post kind of spells out some of what I have been experiencing.  On my Pentax bodies I always underexposed by 2 stops and lifted the shadows (to avoid blowing the highlights).  I was kind of appalled by the behavior of the shadows with my a7II.  I mean downright ugly in some cases (could see what appeared to be patterning of the sensor or interpolation artifacts, not sure.  Some of this has been resolved with the uncompressed format RAW file update in Firmware a while back, however, I am still having a difficult time gauging where I want to be when I take a shot.  I recently did an event which took  place in an old church at dusk.  Light streaming in the stained glass with no house lights inside.  I didnt get a single usable shot.  (stills, not video, I should add. And I should add that I am using my pentax glass with the photodiox PK adapter.  Pentax K 30-mm from the 1970s, Pentax 50mm 1.7, Pentax 40mm f 2.8 pancake XS, and an 18 - 35mm lens branded Phoenix f3.5 to f4.5, I think )

 

I tried to follow the advice of some of the Youtubers on "exposing  S-Log 2") which basically states to try and render your negatives as flat as possible and overexpose by at least 2 stops.  So I was exposing to the right and blowing out the stained glass (in all fairness though, that is a challenging situation trying to render in the mid-low to low ranges).  so, for stills, it still kind of has me stumped for trying to produce usable high contrast/dynamic range.  Curious if the entire system might not have a bias in favor of videographers using the pic profiles, S-Log-2 specifically. 

 

Also, the issue of Capture One vs. Lightroom.  I agree that I am getting better looking results with C1.  However, the darks still dont really want to behave themselves all that much.  I should add also, that C1 is WAY more comprehensive of a GUI allowing for very minute detailed adjustments for color.  I primarily work B&W, and am wondering if anyone has any tips for where to set the black-clipping threshold under the options window in C1? 

 

Just basically, I really want to like this camera.  I am not opposed to trial and error on my own, however, the way this camera exposes is --how to put this politely-- in my experience, somewhat "idiosyncratic."  Any pointers would be greatly appreciated.Anything rom Creative Style selections/settings to software settings.  I have even considered it could be my choice of lens mount adapter? Read one review of that adapter (on amazon) claiming that the interior of the adapter was not properly baffled and resulted in off-axis light hitting the sensor at odd angles and accounting for overall sub-par image production. Not sure if this is something to be concerned about.  I think not though as I have also used a Nikon lens with adapter and was having the same issues in post with the shadows behaving is a rather unfortunate way.

 

Even tried shooting jpegs in S-Log 2, however, I was having the same kind of posterization thing having even when trying to darken the shadows.  Not much luck in Raw Therapee either, if anything, the different de-mosaicizing algorithms in RT made me less hopeful than using ACR. 

 

I hate to sound like a hater because they got so much RIGHT with this camera.  This is my first Sony camera, I should add, and previously my main cameras were all Pentax and Fujifilm digital cameras.  While the Fuji and Pentax behave differently in post, they are not as far out there as the Sony, or rather the discrepancy in what to expect at the moment of capture is not as far off between the Pentax and Fuji as it is with the Sony. 

 

Any pointers are greatly welcome and -- again thanks so much!!

 

--g

 

 

 

[gcristia]

sorry -- the post I was referencing can be found here http://www.sonyalphaforum.com/topic/3433-bandingposterization-issues-with-a7ii/

[markphoto4u]

IMHO, exposing to the right and S-Log 2 are end run arounds to avoid learning zone photography. Though S-Log 2 is useful for video that will be processed. I have a a Sony A7ii and can get awesome photos with any lighting condition I have encountered using zone photography. Example: Expose to the right photographers claim they expose to the right, because the sensor saves information that can be recovered in post. This is not what is going on, trust me. What is happening is the light meter in a default "effort" to see the world in neutral gray tells us to expose the very light areas as an under exposure, making the white or near white zones a "happy grey." (Ever shoot a white sandy beach on a sunny day, and get muddy photos?). It is almost counter-intuitive to open up a couple of stops (expose to the right) because it's bright as hell out there. But this is absolutely necessary, to counter the light meter telling us to stop down to make near white look grey. So you say, I know the light meter is getting faked out of its shoes, so I will open up a couple of stops. (Same scenario with snow. How many muddy snow pix have you seen?). In terms of Zone you subtract zone 2 or 3 (light white) from zone 5 (neutral grey) and you get about 2 stops. So you open up 2 stops and wala Ansel Adems, you get you beautiful nearly white sand or snow. OK, you hate any kind of math. Not a problem. Imagine the world is black and white. (Your light meter does. Doesn't matter much if it cost 3K or 500 bucks). Point the camera at something grey like green grass or anything that would look grey. Use that reading and you will think you have the best camera you have ever owned.

So why does exposing to right work so well so often. Because a lot of our photos have a bright sky in them which many times confuses the light meter just like snow or Sarasota sand.

So why are some photographers writing beware of exposing to the right like I am? Because sometime exposing to the right is guaranteed to ruin your photos. This is because dark areas need the photographer to under expose (again counter intuitive if you don't get that the light meter is telling you to make dark stuff grey). Again Zone tells us if your dark areas are 7 or 8 and grey is 5; subtract zone 5 from zone 7, for example, and CLOSE the shutter a couple of stops. (Or just meter off something grey.). Can you see how totally screwed your photos would be if you were exposing to the right. You would be off by 3 or 4 f stops probably. Over by 2 for not compensating for your grey loving light meter, and 1 or 2 more, because some genius is telling you to expose to right.

Now, the reason you are getting artifacts in dark areas (which will be less of a problem if you use Zones or meter off grey) is do to something called "shot noise." Every sensor is subject to shot noise. Again it doesn't matter if the body is expensive. You can google shot noise, if you are still reading this lengthily piece. Suffice it to say, here, that you do not want to expose to the left and bring your photos up to the "right exposure." You will see all kinds of shot noise and artifacts, as it sounds like you are familiar with these results.

Hope this helps. Some of this may just be a review, and I don't mean to insult anyone's intelligence, but I do know photography. Been doing it for decades; read thousands of articles and a good many books. Started with film in the 70's and have been shooting digital for 15 years. I am a retired pharmacist, and a professional photographer. My website is markwilhelmphotos.com. My prints can be seen at Lilly's on the Lake in Clermont, FL, and Artisans on fifth in Mount Dora FL. If you follow my suggestions, Google and read a little on Zone Photography, and maybe "shot noise," I think you will learn to love that Sony. Good luck and happy shooting.

 

 

markphoto4u

[gcristia]

I know exactly what you are talking about.  I shoot street a little more inland that you ( ha ha ha), but did have the opportunity to shoot a beach volleyball court in bright sun and got amazing results with my Pentax using that method  

 

I guess what I am getting at, is the way the Sony goes about "okay, this pixel is black but this one next to it is only .99% black (not necessarily down to the pixel, but in terms of "this area is dark"). 

 

On the issue of trying to reconstruct highlights, what I have read about S-Log-2 seems to indicate that it is capable of storing more recoverable tonal information in the highlights, so you should instead expose for the shadows and increase exposure.  I have seen the graded (both the good and the bad) footage of video shot this way, and it seems to work in video, but on stills, it just blows my highlights when trying to implement ETTR.  I think I suspected (read: made the assumption based on exposure protocols for SL2) that the sensor is calibrated to optimize the implementation of S-Log-2, since that is kind of like Sony's signature "thing" and that it may have or present (under certain shooting circumstances) implications for those of us on the still photo side of things.  I mean, I've done my fair share of video work before on a Canon GL2 using Premiere and After Effects, about 10 years ago, so I am sensitive to the fact that what videographers want/need in a camera is sometimes different than what the still photographer needs or wants. 

 

  So specifically, perhaps this was more of a technical question that presupposed my (perhaps erroneous) suspicion that there is something about the implementation of the sensor in the a7II that had to be traded-off in order to use SLog2 or offer it on the video side in this camera. My suspicion was purely extrapolated from the items I have read about how to expose SL2 properly.  I suspected that perhaps this (what I consider to be) undesirable behavior of the darks in post was a consequence of SL2 implementation/calibration or something like that....not sure if that makes sense?  However, I know that this camera can produce good results, but I am still in that learning phase.  All the same, I have affectionately nick-named my a7II "Hirohito's Revenge."

It is almost as if rather than giving me a true reading of what is going on in my darks, it interpolatetes everything in a dark region -- like it is applying a curve to the darks that at times can result in unnatural looking images.  My history is in drawing and painting, and it is as if it blocks out the darks the way you would do at the beginning of a realistic charcoal sketch -- outlining the area you intend for the shadows, highlights etc..  When I put the clip warning on and adjust my darks you can see it coming and going.  Its almost  the opposite of the "blooming" of highlights you get if you are using Picasa. Or rather, the same problem except that it occurs in the darks rather than in the highlights.  

 

 

I agree with you that ETTR is counter intuitive, and perhaps counter productive.  Thing is, the Sony has this amazing feature which provides real-time exposure and DOF preview, but when I take the shot using the method you kind of describe ( What I would usually do is spot meter at the brightest thing in the frame, and dial it back by two stops from there, usually in terms of shutter speed rather than aperture unless the light was REALLY fussy.  Shooting street I liked to keep it at around f/8 to f/11. I was getting amazing files from my Pentax K-01...a camera with no viewfinder and no exposure preview (at least not as sophisticated as the Sony's -- it was more on par with the way a point & click meters).  The result I saw when I chimped (on the k-01)  usually showed me what the potential of the negative file was in terms "what could I reasonably expect to be able to correct to in post?"  With this Sony, there is the usual discrepancy between what I see in the VF and what my negative looks like, but it seems like the files give WAY less latitude for editing in either Lr or C1.  Cant figure it out. 

 

 

I am in the process of (trying to) go pro, and I am just trying to get a grip on post with these files.  I guess the crux of my question is, is there something that can be done at the time of capture to ameliorate the ink-blotting effect I get when I try to darken a shadow and conversely, the patterning I am seeing in when I try to lighten?   Are there rules in terms of how much one can lighten a shadow.  The Sony claims a 10 stop (is that right? +/- 5 EV?) dynamic range with this camera. Id like to be able to use every bit of that but I am having a heck of a time of it.

 

Again, I want to say that I am not slamming the a7II, just trying to gain a better understanding of how it understands light and shadow.  Otherwise, I really love the camera and do plan to continue with it, however with Pentax having just announced the K1, their first FF camera, the temptation is there to switch.  I am hoping this is just a "lovers quarrel" with the a7II, as it is a way more versatile machine (specifically the short flange distance being a boon as far as I am concerned when it comes to having legacy lens choices -- they always say a camera is only as good as its glass, so in this respect, the a7 series enables the broadest palette to choose from) in much smaller package (and I dont really need 36 MP from the Pentax).  And I'd hate to trade-in the Sony if this is more of a user error (or worse, if I am just being too picky or something. That possibility has also crossed my mind) type of thing. 

 

In any case, thanks for the replies!

[Golem]

I read an returned some book on Zone System for digital.

Unreal. There is no point in pretending to adapt a system

based on the response curves of film and paper, souped

at modified times and dilutions, to the digital realm.  

  

It's phony. While there are ways of taking better control

over digital imaging, it's stoopid to pretend that the Zone

System has been adapted when doing that. The monster

irony here is that the Zone System is in itself a retreat

from facing technology directly. The Zone System could

also be called The Dummies Guide to Sensitometry and

Densitometry. A kinder, more polite way of saying the

same thing, and also putting it in its original context, is

"The Zone System - Chemical Photography Technology

Reconfigured for Technophobic Artistes". 

[markphoto4u]

Golem: This forum is simply a place where one photographer tries to help another based on a question or problem at hand. Calling someone "stoopid" is non-productive. I am not pretending anything. Understanding Zone Photography and shot noise, IMHO, will cure many problems, and make one a better photographer in the process. If you think photographers like me, who use Zone Photography for film and digital don't know what is going on, feel free to look at my website: markwilhelmphotos.com. In the mean time, please try to keep your comments of a constructive nature. Try offering solutions rather than sarcasm and unhelpful criticism of techniques you don't understand or agree with.

 

 

markphoto4u