Klaus mentioned the use of hyperfocal distance in the recent UWA reviews. I never use hyperfocal distance anymore myself (only tried to use that when I first started to use first DSLR). SInce then I have gone back to focussing on the main subject again, or the furthest away element in land/city-scapes that I want to have detail in.
The "Merklinger" method gives better results than hyper focal distance, which maybe should be treated as a relic from the past...
http://www.trenholm.org/hmmerk/DOFR.html
I'm a fan of Merklingers method since I tested the same things that
Merklinger did myself. Nevertheless, "hyperfocal distance" focussing
does work (and Merklinger never said it doesn't) ... the thing is ... comparing
Merklingers method to the hyperfocal-distance method, you will find,
that Merklinger's method can improve a lot of areas whereas it makes only
few areas worse ... so, if you just search for the worst part of the image,
you'll find that a "Merklinger image" contains it ... if you look for the best
over-all imagequality, you'll find that it is also the Merklinger image that
has it.
"The general rule for scenic photographs, where one wishes to maximize the depth of field, is as follows. Set the focus at the distance of the most distant object. Then set the lens opening to the size of the smallest object to be resolved in the foreground. No calculations needed!"
How can we get the size of the "smallest object to be resolved in the foreground"?
I really would like to apply this in landscape shots and guessing the focusing distance is not so easy...
Serkan
[quote name='Brightcolours' timestamp='1315294643' post='11336']
Klaus mentioned the use of hyperfocal distance in the recent UWA reviews. I never use hyperfocal distance anymore myself (only tried to use that when I first started to use first DSLR). SInce then I have gone back to focussing on the main subject again, or the furthest away element in land/city-scapes that I want to have detail in.
The "Merklinger" method gives better results than hyper focal distance, which maybe should be treated as a relic from the past...
[url="http://www.trenholm.org/hmmerk/DOFR.html"]http://www.trenholm....mmerk/DOFR.html[/url]
[/quote]
Actually I'm never really using the HFD according to the formula. This doesn't make much sense anyway because field curvature spoils the game here. I'm merely using it as "a message" here that AF sucks with ultra-wides.
I could, of course, elaborate on the details but this would take longer than the review ... and as such it would miss the point.
Very interesting. Then it implies that, if you focus a 20mm lens with f/10 at infinity, then anything larger than 2mm will be resolved, right?
[quote name='Frank' timestamp='1315324561' post='11345']
Very interesting. Then it implies that, if you focus a 20mm lens with f/10 at infinity, then anything larger than 2mm will be resolved, right?
[/quote]
This method assumes a flat focus field. Better make sure that you apply it only for qualifying lenses ...
[quote name='Klaus' timestamp='1315326055' post='11346']
This method assumes a flat focus field. Better make sure that you apply it only for qualifying lenses ...
[/quote]
It does not assume that anymore or less than hyper focal distance....
Hyperfocal formulas are too generous. Circle of confusion values should be updated for 100% Photoshop zooming <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/rolleyes.gif' class='bbc_emoticon' alt='
' />
http://flickr.com/ephankim
[quote name='Brightcolours' timestamp='1315331044' post='11347']
It does not assume that anymore or less than hyper focal distance....
[/quote]
Well, the Sigma 12-24mm images at 12mm are reasonably sharp in the corners when choosing a focus distances that is closer to the HFD. At infinity focus the corners are very smeared in the foreground.
The HFD is invariant of field curvature as you mentioned, yes, but in practical terms it is more useful with ultra-wides where a negative field curvature (the corners of the focus field are "pushed" towards infinity) is actually more common (to a varying degree) than a flat one.
[quote name='Klaus' timestamp='1315339679' post='11350']
Well, the Sigma 12-24mm images at 12mm are reasonably sharp in the corners when choosing a focus distances that is closer to the HFD. At infinity focus the corners are very smeared in the foreground.
The HFD is invariant of field curvature as you mentioned, yes, but in practical terms it is more useful with ultra-wides where a negative field curvature (the corners of the focus field are "pushed" towards infinity) is actually more common (to a varying degree) than a flat one.
[/quote]
Ah.. thanks for expanding on that, Klaus. Yes, makes sense for the corners in such a case. I never put too much attention to the corners myself, so my "focus" is more on the main subject(s) and therefore I appreciate "Merklingers approach" myself.
