DIYPhotobits.com Camera Control 2.1 – Greens

UPDATE: Download latest here.

 

You know when you are a kid you have to eat your green vegetables before you are allowed to eat your chips (fries) and all that before you get dessert?  It is a sequence in life — first good-but-nasty, then ok stuff, and finally fun things you really want.

Well for programmers the sequence is:

  • Fix the bugs (Greens)
  • Implement obvious useful but boring features (Chips)
  • Add the fantastic new ideas you just had in the shower (Ice Cream)

So welcome to DIYPhotobits.com Camera Control 2.1 – the Greens release!

DOWNLOAD 2.1

(200KB)

This fixes inumerable small bugs — nothing earth shattering but some annoying things have been fixed.

Bugs fixed:

  1. Error on duplicate download of images is fixed
  2. Default file location is now My Pictures to avoid the issue of the default location not existing
  3. Exposure Compensation drop down now shows proper stop values
  4. Shutter, Aperture, ISO, WB and Exposure Comp drop down boxes initiate to the value on the camera intead of meaningless defaults.
Minor improvements
  • It doesn’t make a temp directory any more
  • Battery meter works all the time, not just when tethering

New limitation discovered

  • Due to the way WIA is working if you want to be able to control shutter and exposure from the PC you must start up with the camera in M mode.  It isn’t good enough to switch to that later after starting up in another mode.

That’s all for now — I’ve already spent most of the day doing this while I should have been working!

Meanwhile I can go back to dreaming about the ice cream — bracketing, time lapse etc…

Amature, Professional or Master?

I saw this quote in a sig — but it was on a German forum and I was reading via Google translator so I’m not sure the original wording.  But I love the quote, if you know where it comes from originally let me know!

  • Amateurs worry about their gear
  • Professionals worry about the profit
  • Masters worry about the light

I recognize myself in that first one!  🙂  But I’m trying to think about light more — people in the street must find me strange when I suddenly stare at the palm of my hand, but I’m looking at how the light is falling on it.  Palms being a good substitute for faces when it comes to exposure.   Here in the city in autumn there are often interesting effects as the sun low in the sky reflects from glass walled buildings, sometimes once or twice, to produce natural cross lighting.

DIY Grey Card

I was checking out Profotolife’s list of cheapo photo gifts and one of the suggestions was a set of grey cards, and that reminded me I always wanted to do a print my own grey card.  Now a grey card, like the “real” Kodak Gray Card 18% R-27 or the cheapie Mennon ones I use, are actually painted pieces of card that are of exactly neutral grey (18% aka Zone 5) and are used for two purposes:

 

  1. To set Exposure — because meters are expecting 18% grey
  2. To set White Balance — because they are designed to be of completely neutral colour
It’s really useful if you are doing landscape photography

, in low light,  or care a lot about colour accuracy for example with product shots.

 

Now before you tell me let me say I already know that it is impossible to print your own grey card that can serve either of these purposes accurately.  The paper and inks that we use at home in ordinary inkjet printers are not going to give accurate results, there will be a colour cast, and the density is not going to be right.

If you have a top of the line printer, proper photo paper and inks, and are printing with a properly calibrated printer profile then it is going to be better — but it still won’t be accurate when seen under different types of lights.  e.g. it might be right in sunlight, but in shade it’s wrong.

So, this is impossible – so what am I writing this about?  Well I know it’s going to be inaccurate but the question is how inaccurate and is it better than nothing?  

Also given that I’ve mention I have a real grey card why should I want to DIY print my own on an inkjet printer?  Well I do have a valid answer to that — the cards themselves are a bit bulky and rather fragile (gets marked so easily) so I tend not to carry them around.  Hence they don’t get used much which sort of defeats the purpose.  If I could print my own I could carry them all the time because I would make small ones and be able to make new ones if they became damaged.

Therefore, on to the test!

First step is to make a Photoshop file and fill a rectangle on it with 18% grey.  So what colour is that?  If you think in 8 bits like me then I’d guess that would be RGB values of 127 127 127 — however I’ve seen a good argument made that it should be 118 118 118.  So I tried both and at least for me the 118 is better — that may well be an accident of my printer/paper/ink combo.

 

This was on 3rd party noname coated matt “inkjet paper” which actually prints ok on my HP OfficeJet 5500 which is a 4 ink printer.  All the printing was done with all colour management off (both photoshop and the printer driver) as I don’t have believable profiles for this printer.

 

Now the tests

Exposure

Testing at ISO 100 (well, “L1” on my D300 which is ISO100 equivalent) at f/16 in bright sunlight at midday gave me:

 

  • Mennon grey card – 1/125s
  • DIY 127 – 1/250s to 1/200s
  • DIY 118 – 1/125s to 1/160s 

That’s using spot metering in the middle of the card, getting up close and out of focus to average things out.  And yes the DIY ones seemed more variable and sensitive to slight changes in position or angle than the real card.

 

So generally the DIY grey card at RBG of 118 118 118 was more accurate — close enough to be usable, certainly if shooting RAW with that stop or stop and a half lattitude you get with RAW.

But how about for colour correction?  To me that’s more interesting really as exposure meters in matrix mode are really perfectly good enough, and you can always chimp the histo or look at the blinkies if you have some extreme cases.

Colour White balance setting

So using the DIY Grey card for WB correct is the next thing to test — and again results will vary wildly depending on printer and paper but for myself the results were mediocre at best.   I printed out a sheet and then shot the real grey card beside the DIY one under different light sources — then in ACR I measured the WB using the dropper tool from the different greys and also from the “white” paper. 

Results:

Sunlight

 

  • Real grey card – 5150K +8 tint
  • DIY grey card – 6000K -5 tint
  • White paper – 5450K -10 tint

Shade

  • Real grey card – 8700K +16 tint
  • DIY grey card – 10750K +8 tint
  • White paper – 12000K -1 tint
CFL – Compact fluorescent lamp
  • Real grey card – 2750K +26 tint
  • DIY grey card – 2700K +15 tint
  • White paper – 2750K +18 tint
Tungsten

  • Real grey card – 3150K +1 tint
  • DIY grey card – 3250K +18 tint
  • White paper – 3150K -9 tint
Fluorescent 
  • Real grey card – 5900K +40 tint
  • DIY grey card – 6750K +28 tint
  • White paper – 6050K +30 tint
I graphed a bit of this and it doesn’t show a lot of pattern I think — neither they DIY card nor the white paper gave accurate readings (which I define as being the same as the grey card).   So is the DIY grey card better for this than simply white paper?  Yes and no, it depends on the light.  
For your amusement here are the test files I used:
So that’s the end of my print-your-own DIY Grey card adventure.   I think I’ll start carrying a piece of folded up A4 white paper in my camera bag — yes printed fake 18% grey on one side — because it is better than nothing, or taking a WB reference point from someone’s shirt collar or a piece of concrete (which is often pretty “mid grey”).
But now at least I’ll have a good concept of how inaccurate it is — namely very!
Update:
Hm….  Maybe I’ll go back to “white” paper…

Bamboo backdrop stand

The other day I saw this nice post at diyphotography.net about a simple backdrop stand, and it made me think how I do this with bamboo.  Nothing bamboo specific about it I think, and in fact really not much to it at all.

Basically I leverage chairs , specifically any chair with straight legs (so no sofas or lazyboys or office spinners).  Why?  Because chairs are everywhere, and they tend to stay put — they are easy to weight down with a few books or you can even have someone sit on it.  So you it isn’t anything extra, it’s just using what you have.

Components

  • Three bamboo poles — at least 6 foot long, dirt cheap where I am
  • A roll of 3M scotch bundling wrap — this is GREAT stuff, strong yet soft enough it doesn’t damage fabric it rubs against.
  • Couple of pieces of elastic cord tied in long loops — I carry some of these everywhere

And then the backdrop, I have a few meters of sheet material from a fabric shop which is almost completely white — and once it is blasted with enough light it is white.  For colour backdrops I just ad gels (to the flash).

Then I need to find two chairs — dining chairs are great though I also use some rattan arm chairs  — then put a bamboo pole upright next to leg of the chair and bind it top and bottom of the chair-leg with bits of velcro.  If the chair back has exposed poles you can bind to all the better for stability.   That gives me two uprights.

Now I take the third pole, stand on the chair to reach, and bind the horizontal pole to the upright with elastic cord giving me an “H” shape of poles.  It takes longer to write it down than to do it and it’s lightweight yet sturdy and all I have to carry about is three poles and the rest goes in my pocket.

I guess this is one up on the “clamp the sheet to a bookcase” in terms of flexibility of where you can put it, but is similarly basic.  But then that’s all you need really isn’t it?

Having said all that — I’ve lost interest in the idea of white backgrounds and really want to find more interesting textures out in the real world to be the backgrounds in my portraits.  But that’s another story.

CC2: Oh what a lot of bugs!

Man I knew I shouldn’t have released this — Camera Control 2.0 is stuffed full of bugs.  None destructive, but they are bad enough to interfer with happy usage of the tool.  

Two are biggies:

First of all for those people getting the “Error: File already exists” error — that was also in 1.0 — and it is caused by using the Shutter Release button while the Start Tether button is down.  Just use one (Shutter Release with the “Download Immediately” ticked -or- use the Start Tether to do continuous tether) and it will be ok. 

Secondly you only get the full set of exposure mode controls on screen if the camera is in M mode when you connect it.  

Also it fails to create the default c:\tethered directory…

I’ll try to fix these today and put out a bug fix but I have to go do some work soon so might not make it – gotta earn a living you know…