Recently when I was photographying sloth bears at Daroji badly needed hyperfocal distance chart for different focal lengths ranging from 12mm to 24mm at different f-stops. While depth-of-preview button gives nice visual feedback of depth I often ended up wanting more dof when I open see the image at its actual size on screen and in print. Though there are nice DoF calculators I felt it is desirable to have a short printed chart which covered my entire focal range (12-24mm) in a single handy chart. So I made this small chart which covers focal lengths from 12mm to 24mm (for 1.5x croped body). Please feel to print a copy for your personal use – may be useful for landscape work too. DoF numbers will be very slightly higher for those bodies with 1.6x crop factor.
DoF Chart from 12mm to 24mm (for 1.5x crop sensor)
Hi Ganesh, Thanks for the useful information. One question is do you think it makes sense to make such a chart for long lenses ( ~600mm ). Was trying similar stuff in kutch with long lenses was not very successful though mainly because going beyond f/16 though dof increased diffraction started kicking in.
Additionally do you find the distance scale in the lens accurate to do the calculation or is there an alternative ?
Comment by Mahesh Devarajan — March 28, 2010 @ 2:34 pm
Mahesh, I rely on depth of field preview botton for my long lenses. Normally dof varies very slightly between f4 to f11 on long teles. For example dof of 600mm focussed at 20 ft (typical minimum focus distance for 600mm) at f4 is 20ft and at f11 19.9ft. At these slight differences I think depth of field preview button is more effective than such a chart.
Comment by ganesh — March 28, 2010 @ 2:52 pm
This is very interesting Ganesh and I think can make life quite easy. But in the field often we need to depend more on approximation with long lens rather than knowing exactly the distance between the lens and the subject. What do I do then ? I have a sigma 10-20, how I calculate the DoF for that ?
Comment by Nilanjan — March 28, 2010 @ 3:53 pm
Nilanjan, as I mentioned above it is mostly useful for wide angle lenses. Only focal length matters. The same chart is useful to (12mmto 24mm). You can add data for 10mm and 11mm using dof calculator.
Comment by Ganesh H. Shankar — March 28, 2010 @ 4:09 pm
Not sure if you have seen this Ganesh. Thought will share it with you. Thom Hogan’s article on hyperfocal distance.
http://www.bythom.com/hyperfocal.htm
Some interesting points to think about.
Comment by Mahesh Devarajan — March 29, 2010 @ 4:04 am
Mahesh, thanks for the link – not sure what all those hypes are that he talks about in the article. I think “techniques” are means to achieve an “artistic” end product – we should not be discussing them as an end in itself. But they are important for an artist to know. The chart is a result of the need I had in the field a few weeks back – not the result of “arm chaired (internet) photography”
My main use case here for me was unmanned wide angle photography using remote passive infrared triggers where it is difficult to precicely know in advance where your animal will show up in the frame – thanks nature of passive infrared triggers. For example I was badly in need of this chart to make an image like this below -
http://www.naturelyrics.com/galleries/fauna/pages/bear_at_night.html
It did not come out the way I anticipated but I am now better prepared to make such images.
The challenge was I had to focus at minimal possible distance to keep the “wide angle” effect and be confident of getting the bear sharp even if it shows up in sub-optimal places inside the frame. Also I may not want to take very safe approach of stopping down to f22 too for obvious reasons. I had this exact need for this image below –
http://www.naturelyrics.com/galleries/fauna/pages/bat_flight_night_gd1.html
So, is it hype ? may be if we are discussing it as a technical subject – definitely not for me
Comment by Ganesh H. Shankar — April 2, 2010 @ 2:06 am
Even I did not completely subscribe to Thom\’s view Ganesh. In the middle of his technical explanations the point that caught my attention was when he says depth cue might be lost when all objects from near to infinity are kept in focus. Had never thought in that direction. I liked your usecase explanation and why hyper focal distance calculation is essential to factor the fact the bear could be appearing anywhere in the frame. Had not thought in this direction either
Think these insights comes only from practical field experience. I think what Thom says might hold good only when someone is behind the camera where the person can go by his instincts to decide on depth of field and does not hold good in remote trigger scenarios.
Thanks for your thoughts Ganesh.
-Mahesh
Comment by Mahesh Devarajan — April 2, 2010 @ 4:14 pm
I agree about losing the depth cue here Mahesh. However I think that is easier to handle compared to subject being out of focus due to lack of depth.
Comment by Ganesh H. Shankar — April 3, 2010 @ 8:12 am