kenArchi wrote:
Isn't f4 or f5.6 is where the lens is at it's sharpest?
My 560 f/6.8 Leitz Telyt is terrible at f/5.6.
CHG_CANON wrote:
"f/8 and be there" assumes you couldn't afford better equipment.
My guess is that f/8 is a ballpark value based on DOF requirements in a very general sense.
If your love is Portraiture, then stay away from f/16, f/22, f/32, et al. If landscapes are your "thing", huge DOF is worth a small amount of often unnoticeable "diffraction blur."
wdross
Loc: Castle Rock, Colorado
kenArchi wrote:
Isn't f4 or f5.6 is where the lens is at it's sharpest?
As others have mentioned, it is very dependent several factors. Some are lens design, lense construction ( specifically the aperture iris), and format. Diffraction is the biggest culprit at larger apertures for loss of sharpness. Some lens designs will provide the sharpest image in the f4/f5.6 range. But most designs provide the sharpest images at f8/f11 for 4/3rds format and f11/f16 for full frame. Diffraction is one of the downsides of smaller formats relative to larger formats.
Many lenses are indeed at their sharpest at f4 or f5.6 depending on the maximum aperture of the lens. Would you shoot a landscape at f5.6 because that will be the sweet spot of the lens in use? I do not think so. So, why f11 or f16?
It has been already mentioned, because of the depth of field. Lenses can only focus on one spot or only a part of the subject. It is the depth of field or the apparent sharpness between foreground and background the main reason for using small lens apertures for landscapes.
Diffraction or the bending of the light rays as they pass through the diaphragm of the lens causes blur to images but I will tell you that refraction has never stopped me from shooting at f16 or f22. If the blur is there and it should be, sharpening of the file makes it practically unnoticeable.
Im not into physics of the lens aperture and diffraction but in your 3 charts, I assume that the blue shadow belongs to the diffracted areas and the pink, the sharper field.
On the topmost short, I can see a big difference but on the bottom chart, there appears to be a constant and narrower diffraction as you increase your F stop from 9 to 22+.
I would like to know which lenses you have used in these 3 charts.
Does the quality of the image change if you use Kit lens VS Prime?
Does the maker (brand) make a difference in the outcome of the picture taken using similar settings?.
I like to take landscape, cityscape and seascape so I am curious if sharpness is really that important in the
background. Color fringing is what I don't want to encounter.
Some photographers are F11 stoppers and others are F16 stoppers and there are even Clubs who adhere to these settings like the Blue and the Red.
There are many situations where using hyperfocal distance doesn't give useful values until you get above about f/11.
billnikon
Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont
kenArchi wrote:
Isn't f4 or f5.6 is where the lens is at it's sharpest?
Generally speaking, a lens is at it's best two or three stops down. I also avoid F16 to F22 when ever possiable.
billnikon wrote:
Generally speaking, a lens is at it's best two or three stops down. I also avoid F16 to F22 when ever possiable.
I avoid splitting hairs over numbers whenever possible.
I just use the lens.
There's a movie titled "f/11 and Be There", about Burk Uzzle, the youngest photographer ever hired by Life Magazine.
However, the term was originally "f/8 and be there", and it long precedes the movie. The old press cameras frequently had 135-150mm lenses which had a max aperture at around f/4-f/5.6. Two-to-three stops down was f/8, the sweet spot of these lenses. It was an optimal combination for 4x5 sheet film, and the large "press flash bulbs". It was popularized with Weegee, the famed news photographer from the 30's to the 50's. He was famous for his gruesome crime scene photos, as well as being a paparazzo.
Small stops are a primary reason/use to increase depth of field.
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