Questions that you've always wanted to know the answer to

[brammers]

I'd been wondering for ages which order to add adjustments in in Lightroom. Should I do noise reduction before sharpening or vice versa? Levels before broad histogram adjustments or should I tweak the highlights first and then adjust the histogram to match? Do you add a vignette before or after you cross-process the colours, and if you later remove the vignette does it deteriorate quality?

Well the answer is really simple but I didn't know for ages - it doesn't matter because LR only applies the adjustments you made upon export, and then it chooses the most efficient order in which to do so.

This inspired me to ask a few more questions that I'm not quite sure on the answers to in the hope that I can get some definitive responses. Feel free to ask your own little niggles, maybe I can even answer one or two myself!

1: When shooting jpgs WB is very important - get it wrong and you can have big problems correcting your image as some colours clip faster than others. We're told to shoot RAW to compensate - but is there any point in still trying to match WB in-camera other than to aid speed/accuracy in PP later? Is WB stored like exposure, where you get more leniancy in RAW but there's still only so much it can do, or is it the case that you'll always be able to get just as good a result from tweaking even the most awful attempt at AWB in RAW as you would if you'd nailed the WB at the time of shooting?

2: I've read a lot about the difference of FoV and perspective when going from APS-C to FF. I know that DoF is a function of aperture and distance to focal plane. I've also noticed sensor magnification creeping into some definitions of DoF. If I take a 200mm lens on a FF camera and a 135mm lens on an APS-C camera with the same aperture, same framing, same shooting position does the FF camera give less DoF? Sensor magnification says it should. Is this why proponents of medium and large format talk about the 'look' that those formats give - even though I can match their f-stop, FoV and perspective, I can't match their sensor magnification with a FF sensor.

What if I shoot my a900 using APS-C mode? Does that give the same DoF as an APS-C camera with the same lens, or less?

[Bobster]

Should I do noise reduction before sharpening or vice versa?

sharpening always at the end, i don't sharpen any image ISO800+ i also don't apply any noise reduction other than the basic default in ACR (single image editing) or C1 (batch), and sometimes turn it off all together..

Levels before broad histogram adjustments or should I tweak the highlights first and then adjust the histogram to match? Do you add a vignette before or after you cross-process the colours, and if you later remove the vignette does it deteriorate quality?

all basic exposure adjustments are made before any editing so exposure / curves / saturation - then editing..

i don't use Lightroom so don't know the full ins and outs - i used it for about 30 mins when testing it out a couple of years ago, but didn't like the interface so stuck with CaptureOne..

1: When shooting jpgs WB is very important - get it wrong and you can have big problems correcting your image as some colours clip faster than others. We're told to shoot RAW to compensate - but is there any point in still trying to match WB in-camera other than to aid speed/accuracy in PP later? Is WB stored like exposure, where you get more leniancy in RAW but there's still only so much it can do, or is it the case that you'll always be able to get just as good a result from tweaking even the most awful attempt at AWB in RAW as you would if you'd nailed the WB at the time of shooting?

I've always left my WB on Auto when shooting RAW, you can try and match the WB to begin with, but so much time is taken by doing that, i shoot a white balance chart when in difficult lighting conditions so i can refer to that when doing WB later. Only real pain in the rear is when Red light is used, no amount of RAW PP is going to save you from the dreaded Red lights, only real save on that is a B+W conversion!

2: I've read a lot about the difference of FoV and perspective when going from APS-C to FF. I know that DoF is a function of aperture and distance to focal plane. I've also noticed sensor magnification creeping into some definitions of DoF. If I take a 200mm lens on a FF camera and a 135mm lens on an APS-C camera with the same aperture, same framing, same shooting position does the FF camera give less DoF? Sensor magnification says it should. Is this why proponents of medium and large format talk about the 'look' that those formats give - even though I can match their f-stop, FoV and perspective, I can't match their sensor magnification with a FF sensor.

What if I shoot my a900 using APS-C mode? Does that give the same DoF as an APS-C camera with the same lens, or less?

i'll ask a few people i know to shoot the same subject with their FF and crop cameras and get back to you on that

[brammers]

Thanks for having a crack Bobster. The LR questions were rhetorical - none of those decisions matter because LR chooses the optimal order to apply the processes at the end, upon export. But yes, if I was using PS or the like I'd agree with your order.

I agree that setting WB can be a biatch - although I've definately found it less of a problem recently than before. But is there any quality difference between getting WB right at capture and getting WB right in PP?

If I shoot a load of shots with -1EV exposure comp set I know that I can recover the shots in LR with a minor loss of quality - the shots will be a bit more noisy.

If I shoot a load of shots in JPG in daylight using flourescant WB I know that I'm going to have a problem getting the green cast out of the images - the jpg has simply discarded the info used to make the colour cast normal and I'll very quickly clip colour channels when getting back.

If I shoot a load of shots in RAW in daylight using flourescant WB, although I can fix the result later, is there any image quality penalty to doing so? I'm often quite suprised by how WB alters the histogram - going to a warmer WB will often reduce highlight clipping.

Where is WB info taken from? It's not a physical variable like a shutter speed - which tends to suggest that there's no quality loss from doing what you want with the RAW... I dunno - I've been quite suprised by WB's power recently - not trying to force the WB has led to much smoother images recently.

Look forward to results from your friends

[kalniel]

But is there any quality difference between getting WB right at capture and getting WB right in PP?

To answer your exact question: no.

WB is a purely post process stage, whether applied by the camera in convertion to jpeg or by yourself in dealing with the RAW. If you don't think you're touching the whitebalance when dealing with RAW it's only because the program you are using is clever enough to pick up the profile of your camera and set it to the camera's recommended whitebalance settings for that photo. If you turn this feature off in your image program then you'll see the 'real' whitebalance which looks horrible. So it's already being 'corrected'.

Where is WB info taken from? It's not a physical variable like a shutter speed - which tends to suggest that there's no quality loss from doing what you want with the RAW... I dunno - I've been quite suprised by WB's power recently - not trying to force the WB has led to much smoother images recently.

The camera records the information as a colour profile which is embedded as metadata in the RAW file.

If I get time tonight I can show you some examples of not using a camera's colour profile to see what it's like before you correct WB - it's quite easy for me to do this because the free program I use for RAW can't cope with the colour profile for RAWs from my camera - because I'm using a canon A series powershot which isn't meant to save RAW in the first place So by default I see the 'real' colour balance which tends towards green (more green sensors) - I have to either correct this myself or use an intermediate program which can read the camera colour profile and convert it to a format recognised by RAW Therapee.

[brammers]

Cool - so jpgs can't be colour corrected as easily because the info used to do so is thrown away when the jpg is made, based upon the WB reading at the time.

RAWs can be colour corrected because the WB reading is nothing more than a number saying 'apply this cast to the whole shot' which you can override in the presence of the whole sensor readout later.

That's how I thought it worked, was never 100% sure though