Open

by damned truths

submit your photo


Hall of Fame
View past winners from this year

Please participate in Meta
and help us grow.

95,120 reputation
3198351
bio website mattgrum.com
location
age
visits member for 4 years, 3 months
seen 20 hours ago

Oct
28
comment Why Isn't This Photograph Pin Sharp?
@IliahBorg I don't use DOF calculators either, I use live view at maximum magnification centred on the most distant detail I want to capture and starting at infinity bring the focus forwards as far as possible until it just starts to degrade.
Oct
28
revised Why Isn't This Photograph Pin Sharp?
deleted 1 character in body
Oct
27
comment Why Isn't This Photograph Pin Sharp?
@IliahBorg See my response to Pedr, above. When using a more appropriate value for the CoC such as 0.007mm (a bit pessimistic, but good for illustration) the DOF only extends from 26m to 54m, a good deal short of infinity. So you can indeed get the background to be noticeably blurred when examining the image close up, and in fact that can be seen in the RAW file. Even if you want a pin sharp background focusing at infinity is rarely a good idea, focusing slightly in of infinity will give you a huge increase in DOF.
Oct
27
comment Why Isn't This Photograph Pin Sharp?
@Pedr beware of DOF calculators, they assume a very old standard for what is "sharp" based on viewing a small print from a certain distance. Most DOF calculators assume a blur of 0.025mm wont be detecable, but the pixels in a 5D mkIII are only 0.00625mm apart, so a 0.025mm blur will cover about 10 pixels! Sometimes you can enter your own value for the acceptable circle of confusion (blur radius), I suggest you use something like 0.007mm to be on the safe side.
Oct
27
answered Why Isn't This Photograph Pin Sharp?
Oct
27
comment What is the benefit of a wide-aperture lens if you stop it down?
You stop seeing an improvement in viewfinder brightness at about f/2.5 (depending on the particular focusing screen used), so there is a benefit to using an f/2.8 rather than f/4 lens.
Oct
27
answered Can the method from the paper “High-Quality Computational Imaging Through Simple Lenses” compete with conventional lenses?
Oct
27
awarded  Nice Answer
Oct
26
revised What is the benefit of a wide-aperture lens if you stop it down?
added 678 characters in body
Oct
26
comment What's the dynamic range of the iPhone 6 Plus?
Dynamic range is a concept with a simple definition - it is the difference between the saturation point and the point at which noise overcomes any image detail. The different numbers are the result of using different value for the maximum noise level. DxO use a signal to noise ration of 1 (noise is equal in magnitude to the signal), I'm not sure what DPR use as I don't think they've published it.
Oct
26
answered What is the benefit of a wide-aperture lens if you stop it down?
Oct
23
awarded  Enlightened
Oct
23
answered How does a modern DSLR camera and lens actually adjust its aperture
Oct
21
awarded  Nice Answer
Oct
20
answered What is a pump zoom lens?
Oct
20
comment Is there a viable way to touch up the paint on an old camera body?
I've heard of people using lead-based touch-up pens designed for firearms, depending on what country you live in they could be easy or difficult to get hold of...
Oct
20
answered Do focal length changing lens adapters affect the F-stop of a lens?
Oct
16
awarded  Good Answer
Oct
15
revised Do I use the crop factor in calculating aperture size and area?
added 14 characters in body
Oct
15
awarded  Nice Answer