Mark Baigent Posted February 6, 2014 Share Posted February 6, 2014 Hi All I should know this but.... can any one point me at the formula for comparing depth of field at different apertures for different sensor sizes. In my head I know what depth of field I can expect for a given aperture using my Full frame kit. But I cannot visualise this for an APS-C sensor. ATB Mark Link to comment Share on other sites More sharing options...
SShep Posted February 6, 2014 Share Posted February 6, 2014 Here you go Mark: http://www.dofmaster.com/dofjs.html I think this is what you're after. Steve Link to comment Share on other sites More sharing options...
Mark Baigent Posted February 6, 2014 Author Share Posted February 6, 2014 Thanks Steve Very useful ATB Mark Link to comment Share on other sites More sharing options...
David Kilpatrick Posted February 6, 2014 Share Posted February 6, 2014 Mark, I'm working on this for the next issue of Cameracraft - with difficulty. I have come to realise that this is not the simple formula it used to be. Sensor resolution also has a significant effect on depth of field especially if you 'view at 100%' - or do the equivalent and use high megapixel count images to mark larger prints, in proportion. The old film-based formula apart from being based on a modest 10 x 8 print hand in the hand does not account for having two formats identical in size, but one twice the resolution of the other - and I've found that the presence or lack of an AA filter also has a significant effect on depth of field, because of the blurring and restoring method (deconvolution and sharpening) used for conventional AA filtered sensors. Link to comment Share on other sites More sharing options...
spacecadet Posted February 6, 2014 Share Posted February 6, 2014 No problem for us chaps with an A55, eh David, boast boast. (for the uninitiated, it has a DoF button which does the job). I'm even getting on quite well with studio flash. Link to comment Share on other sites More sharing options...
Mark Baigent Posted February 6, 2014 Author Share Posted February 6, 2014 Hi David > I'm working on this for the next issue of Cameracraft - with difficulty. I know what you mean, I was looking for the formula that I used in college ( al looong time ago) but I walked into a whole new set of variables > I have come to realise that this is not the simple formula it used to be. Exactly what I found. > Sensor resolution also has a significant effect on depth of field especially if you 'view at 100%' - Which I always do. > or do the equivalent and use high megapixel count images to mark larger prints, in proportion. The old film-based formula apart from being based on a > modest 10 x 8 print hand in the hand does not account for having two formats identical in size, but one twice the resolution of the other - > and I've found that the presence or lack of an AA filter also has a significant effect on depth of field, because of the blurring and restoring > method (deconvolution and sharpening) used for conventional AA filtered sensors. There is a very simple solution, let you do the work and I will buy the magazine........... problem solved. Please let us know when the new issue is available. Mark Link to comment Share on other sites More sharing options...
Mark Baigent Posted February 6, 2014 Author Share Posted February 6, 2014 Hiya No problem for us chaps with an A55, eh David, boast boast. (for the uninitiated, it has a DoF button which does the job). I'm even getting on quite well with studio flash. How does it know what circle of confusion you are using? ATB Mark Link to comment Share on other sites More sharing options...
spacecadet Posted February 6, 2014 Share Posted February 6, 2014 The stop-down DoF corresponds very closely to what one sees at 100%. Link to comment Share on other sites More sharing options...
Mark Baigent Posted February 6, 2014 Author Share Posted February 6, 2014 The stop-down DoF corresponds very closely to what one sees at 100%. That sounds useful :-) Mark Link to comment Share on other sites More sharing options...
Mark Baigent Posted February 6, 2014 Author Share Posted February 6, 2014 To explain my question When I pick up a full frame camera I have a feel for what the different apertures will give me. I know that for interiors I will be somewhere around f16 and for a portrait I will be around f2.8. I was trying to work out what would be the equivalent on an APS-C camera........... just musing while I keyword :-) Link to comment Share on other sites More sharing options...
Allan Bell Posted February 6, 2014 Share Posted February 6, 2014 You could try this one too. http://www.cambridgeincolour.com/tutorials/dof-calculator.htm Allan EDIT: Sorry for some reason link not working. (Come to think of it neither am I.) Allan Link to comment Share on other sites More sharing options...
David Kilpatrick Posted February 7, 2014 Share Posted February 7, 2014 Mark - assuming the same pixel count, say Nikon D4 versus Sony A55 (both 16), it's roughly one stop difference - slightly more, it would be one stop if the sensor had a 1.4X crop factor not 1.5X, say 1.3 stops. So what you get at f/4.5 on the Nikon, will be pretty well matched by f/2.8 on the Sony. MicroFourThirds is about a two stop benefit, so f/2.8 with a similar angle of view and 16 megapixels on the OM-D E-M1 is a more or less a match for f/5.6 on the D4. The Sony RX100/Nikon 1 is fairly close to a 0.7X reduction again in sensor linear size (2.7X crop compared to 2X crop for MFT) and therefore gains just under one stop benefit over that format, near enough two stops over APS-C, three stops over full frame (though the pixel counts at 14 or 20 are not the same convenient exact match as the Nikon D4/E-M1/A55 etc). This is why the RX100 is so good at apertures like f/1.8 or f/2 at its 28mm equivalent end, it's actually like using a 28mm lens at f/5.6 on a 35mm camera, and most users wouldn't say that was extreme. They get nervous about using f/2 and forget it's f/2 with a 10mm focal length. That little camera's lens (set widest angle) is working at its best around f/2.8 to 4 and that is like f/8 to 11 full frame. I really like my Fuji Finepix F770EXR for its even more extreme 16 megapixels - 4.5mm lens, but not on the approved list! Link to comment Share on other sites More sharing options...
Martin P Wilson Posted February 8, 2014 Share Posted February 8, 2014 Mark - assuming the same pixel count, say Nikon D4 versus Sony A55 (both 16), it's roughly one stop difference - slightly more, it would be one stop if the sensor had a 1.4X crop factor not 1.5X, say 1.3 stops. So what you get at f/4.5 on the Nikon, will be pretty well matched by f/2.8 on the Sony. MicroFourThirds is about a two stop benefit, so f/2.8 with a similar angle of view and 16 megapixels on the OM-D E-M1 is a more or less a match for f/5.6 on the D4. The Sony RX100/Nikon 1 is fairly close to a 0.7X reduction again in sensor linear size (2.7X crop compared to 2X crop for MFT) and therefore gains just under one stop benefit over that format, near enough two stops over APS-C, three stops over full frame (though the pixel counts at 14 or 20 are not the same convenient exact match as the Nikon D4/E-M1/A55 etc). This is why the RX100 is so good at apertures like f/1.8 or f/2 at its 28mm equivalent end, it's actually like using a 28mm lens at f/5.6 on a 35mm camera, and most users wouldn't say that was extreme. They get nervous about using f/2 and forget it's f/2 with a 10mm focal length. That little camera's lens (set widest angle) is working at its best around f/2.8 to 4 and that is like f/8 to 11 full frame. I really like my Fuji Finepix F770EXR for its even more extreme 16 megapixels - 4.5mm lens, but not on the approved list! That's the assumption I have used when I use my Fuji X compared to my Canon FF - not quite right I appreciate because of the different resolution 16Mpx v 21Mpx for the FF. I look forward to reading the CameraCraft article when it arrives. Link to comment Share on other sites More sharing options...
Mark Baigent Posted February 9, 2014 Author Share Posted February 9, 2014 Hi David Useful post as always. I now have a my 5D 11s and an X100 it will be interesting to see the comparison. Mark Link to comment Share on other sites More sharing options...
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