Shooting wide open with Digital
Here's a question I haven't seen addressed anywhere. Your thoughts please.
Generally, with traditional film cameras you need to stop a lens down 2-3 stops from the maximum aperature to get optimal quality out of the lens. Correct?
With a digital camera you are capturing the center portion of the image. Isn't a big factor in low image quality with a traditional film camera when shooting wide open due to the falloff in sharpness towards the edges? If so, it stands to reason that you can get higher image quality at wide open aperatures from a lens on a digital camera than from that same lens on a film camera.
Is there anything to this? If so, is the difference significant enough to matter? The main point being whether you can get away with using a lower cost variable aperature lens wide open rather than paying for a f2.8 fixed lens but having to stop down to f5.6 anyways.
#1. "RE: Shooting wide open with Digital" | In response to Reply # 0jnscbl Basic MemberFri 17-May-02 10:27 AM
If you shoot a lens test on film, you will see that the entire image, icluding the center, is sharper when stopped down. On some lenses, the edges are always softer than the center. In this case, cropping will remove the soft edges.
"I am always doing that which I cannot do, in order that I may learn how to do it."
#2. "RE: Shooting wide open with Digital" | In response to Reply # 0GilbertC Registered since 24th Feb 2002Fri 31-May-02 02:15 AM
I'm not yet going digital but the discussion seems to make a presumption that the resolving power of the sensor is higher than a f2.8 lens at f2.8, thus discussing about the soft corner. But in fact if making some calculation about line-pair-per-minimeter of both the sensor and those major f2.8 lenses, current digital cameras is sensor-limited instead of lens-limited.
In my opinion most lenses have more resolving power at f2.8 than the sensor and that's why stopping down doesn't do any good about it.
In fact I plan to go digital when the resolving power of a sensor is close to that of a f2.8 zoom at f5.6.
#3. "RE: Shooting wide open with Digital" | In response to Reply # 0BJNicholls Charter MemberFri 31-May-02 07:09 PM
Of course this is only a concept for consideration with a digital SLR body since digital cameras with built-in lenses have lenses designed to cover a smaller area. Cropping out the edges of a poor performing lens may be a nice thing for some people, but for a good lens there would be no benefit.
Whatever good you might find in using only the "sweet spot" of a lens, I find the drawbacks much more problematic. The D100 would take my superwide 18-35 zoom and cut the wide perspective down to a puny 28mm equivalent. I'd rather have the full field of view with whatever edge softness that may imply rather than lose the characteristics of an expensive lens. I look forward a couple of generations to full frame digital SLR bodies that offer all the flexibility that the 35mm lens systems have to offer.