Setting the correct exposure is one of the most fundamental of photography. With the inbuilt light meters in our camera’s, this becomes a piece of cake as we no longer need to work by the Sunny 16 or any other gothic rule. However over dependence on these inbuilt meters have meant most of the amateur photographers not able to count exposure mentally in terms of stops.
This ability to increase or decrease the exposure by stops comes in handy when one is trying his/her hand at really long exposures. Once you put a dense enough Neutral Density(ND) filter, you will need to count back in stops so as to determine the correct exposure. Depending on the density of your ND filter, this may demand to count back up-to 10 or more stops. Now if you’re sound of your knowledge about the aperture & shutter-speed scale, then you’ll breeze through. Else you might go for the trial & error method. However, the trial & error method would take sometime before you figure out the correct exposure. Instead, use ‘Exposure Calculator‘.
Exposure Calculator is a nifty android application which allows one to calculate exposure for long exposures. One needs to simply input the current correct exposure settings(indicated by your camera’s inbuilt meter) in the top part of the application after which you input the density of your ND filter in stops & you’ve your new exposure automatically calculated for you at the bottom. Makes sure you input the correct settings in the first place else your exposure will be skewed.
That’s it! Now if maths was not your favourite subject in high school, simply use the ‘Exposure Calculator’ & give all the worries of your calculation to your maths teacher. :)
Histogram is perhaps the most neglected aspect amongst photographers. I’ve come across photographers who’re not even aware of what is exactly an histogram. Those who are aware of it just know as to how it looks. They have no clue of what the peaks & canons suggest in an histogram. However to become a photographer of a substance, one must know how to read histograms. Its not rocket since & its fairly easy.
If you’re serious about exposure & colour balance in your photographs, you must use an “18% Grey Card”. Though today Auto White Balance has come a long way & gives pretty great results most of the time, it does gets fooled at times under tricky mixed lighting situations. Here the grey card will come at your rescue. It will also prevent a lot of your time during post-processing & save you the hassle of correcting WB & exposure. In first part of this article, I’ll teach you how to make a 18% Grey Card for yourself. I highly recommend to make this DIY 18% Grey Card to understand(practise) about exposure & colour correction. This DIY 18% Grey Card isn’t technically perfect but will still give you close to accurate results in your photographs. Once you get a hang of exposure & colour corrections in depth, consider purchasing the commercially available Kodak 18% Grey Card for accurate results.
Things you’ll require:
1) Image Editing Software supporting Layers. I recommend GIMP, its great & free too.
2) Printer(Alternately go to your nearest cyber-cafe to take a printout)
3) White Card-Board(Thick)
Click to Enlarge
1) Open GIMP. Hit File>New. In the new file creation dialog box, select A4(300ppi) & click OK.
2) Now go to Layer menu & select ‘Duplicate Layer‘.
3) Now press ‘Shift + B’ to select ‘Bucket Fill Tool’. Ensure that ‘Black’ colour is selected as foreground colour. Now click the cursor on the duplicated layer & the layer should be filled with black colour. Now from the GIMP toolbar adjust its opacity to 50%. Save the file as tiff.
4) Now just take a printout of this file on an A4 paper sheet. After that, cut the printed A4 sheet into four equal pieces & stick the pieces over the white card-board. Ensure you cut the card-board pieces slightly bigger than the grey card pieces so you can hand-hold them without ruining the grey area.
There you’ve it. Your 18% Grey Card is ready to use. Keep these four pieces in a ziplock bag & into your camera bag. In the next article, I’ll teach you how to use these grey cards.