Sweetspot for canon 70d?
Sep 13, 2018 11:04:31 #
For those of you that have done sweetspot testing for their lens sharpness on a canon 70D using aperture priority,on a tripod with shutter release what aperture setting(f-stop) tested the sharpest. If you could give me your results and and what lens. I know a high end lens canon L series or an f 2.8 lens will test sharper,but i use my canon 18-135mm stm mostlyl. Thanks.
Sep 13, 2018 11:05:46 #
The lens has a sweetspot, not the camera. The aperture is an attribute of the lens.
Sep 13, 2018 11:13:56 #
Thanks for clarifying paul but in the first sentence it did say sweetspot testing for their lens sharpness. sorry for the misunderstanding. They can give me the results using any canon dslr crop camera.
Sep 13, 2018 11:20:46 #
redfordl wrote:
Thanks for clarifying paul but in the first sentence it did say sweetspot testing for their lens sharpness. sorry for the misunderstanding. They can give me the results using any canon dslr crop camera.
You know what you were trying to say, but your title says a camera model and the first sentence continues with a camera model and no reference to a lens ....
For professional reviews of Canon equipment, you simply have to visit The Digital Picture
https://www.the-digital-picture.com/Reviews/Canon-EF-S-18-135mm-f-3.5-5.6-IS-STM-Lens-Review.aspx
Sep 13, 2018 11:23:04 #
Sep 13, 2018 16:10:47 #
amfoto1
Loc: San Jose, Calif. USA
What redfordl wrote is correct... that lenses have "sweet spots", not cameras.
Usually a lens' "sweet spot" is an "ideal aperture" or apertures where it gives the best possible combination of image sharpness, minimizes vignetting, controls chromatic aberrations and coma, and has the least distortion. Often it's one or two stops down from "wide open" where lenses give their best performance. But some lenses are optimized for wide open use (such as 300mm f/2.8). Others are optimized for smaller apertures (macro and ultra wide angle). A zoom lens might vary, depending upon the focal length being used.
However, lens image quality actually might differ from one model of camera to the next. In general, the higher the MP or the density of the pixels on a sensor, the more "demanding and unforgiving" of a lens a camera will be. For example, the 50MP 5DS-R is just about the most demanding of all... being full frame AND ultra high resolution AND not using an anti-alias filter.
But if you look at the pixel pitch of the 5DS-R, it's virtually identical to the 18MP 7D. Your 70D (and my 7D Mark IIs) have even "more crowded" sensors, with 20MP on APS-C. And the newer 24MP cameras (all current Canon APS-C models except for 7DII) have even smaller pixels and more crowding. But some improvements in sensor tech and/or processors has helped keep their overall IQ high.
There are other factors. One of the advantages of crop cameras like ours is that when they're fitted with full frame-capable lenses they only use the central, sharpest portion of the image circle. They effectively "crop away" the edges and the corners, where many lenses are at their worst. Of course, that's not the case with EF-S lenses that are designed specifically for crop sensor cameras.
I agree with the suggestion you check out the review and tests of your EF-S 18-135mm IS STM lens at the-digital-picture website. However, you really should run some tests with your own particular copy of the lens too, in order to see what apertures it gives the best performance at different focal lengths. Put your camera and lens on a tripod, remove any filter, focus carefully on a flat subject with a lot of fine detail (such as a brick wall or a weathered wood fence) and make a series of test shots at different apertures and zoomed to different focal lengths. Then inspect those images closely, to see how your lens performs. This will help you decide what settings to use. 70D has micro focus adjustment, too... so you might be able to fine tune focus accuracy with your particular lens.
It's always a good idea to study lens reviews, but there is some "copy variation", so any lens you use should be tested in this manner.
Usually a lens' "sweet spot" is an "ideal aperture" or apertures where it gives the best possible combination of image sharpness, minimizes vignetting, controls chromatic aberrations and coma, and has the least distortion. Often it's one or two stops down from "wide open" where lenses give their best performance. But some lenses are optimized for wide open use (such as 300mm f/2.8). Others are optimized for smaller apertures (macro and ultra wide angle). A zoom lens might vary, depending upon the focal length being used.
However, lens image quality actually might differ from one model of camera to the next. In general, the higher the MP or the density of the pixels on a sensor, the more "demanding and unforgiving" of a lens a camera will be. For example, the 50MP 5DS-R is just about the most demanding of all... being full frame AND ultra high resolution AND not using an anti-alias filter.
But if you look at the pixel pitch of the 5DS-R, it's virtually identical to the 18MP 7D. Your 70D (and my 7D Mark IIs) have even "more crowded" sensors, with 20MP on APS-C. And the newer 24MP cameras (all current Canon APS-C models except for 7DII) have even smaller pixels and more crowding. But some improvements in sensor tech and/or processors has helped keep their overall IQ high.
There are other factors. One of the advantages of crop cameras like ours is that when they're fitted with full frame-capable lenses they only use the central, sharpest portion of the image circle. They effectively "crop away" the edges and the corners, where many lenses are at their worst. Of course, that's not the case with EF-S lenses that are designed specifically for crop sensor cameras.
I agree with the suggestion you check out the review and tests of your EF-S 18-135mm IS STM lens at the-digital-picture website. However, you really should run some tests with your own particular copy of the lens too, in order to see what apertures it gives the best performance at different focal lengths. Put your camera and lens on a tripod, remove any filter, focus carefully on a flat subject with a lot of fine detail (such as a brick wall or a weathered wood fence) and make a series of test shots at different apertures and zoomed to different focal lengths. Then inspect those images closely, to see how your lens performs. This will help you decide what settings to use. 70D has micro focus adjustment, too... so you might be able to fine tune focus accuracy with your particular lens.
It's always a good idea to study lens reviews, but there is some "copy variation", so any lens you use should be tested in this manner.
Sep 14, 2018 10:42:29 #
mwsilvers
Loc: Central New Jersey
redfordl wrote:
For those of you that have done sweetspot testing for their lens sharpness on a canon 70D using aperture priority,on a tripod with shutter release what aperture setting(f-stop) tested the sharpest. If you could give me your results and and what lens. I know a high end lens canon L series or an f 2.8 lens will test sharper,but i use my canon 18-135mm stm mostlyl. Thanks.
The sweetspot is usually when the lens achieves maximum sharpness across the frame. As very a general rule of thumb most lenses tend to reach their sweetspot when stopped down around 2-3 stops from wide open. That means for an f/1.4 prime it may be f/2.8 or f/4, For an f/4 lens it might be f/8 or f/11. For f/5.6 it might be f/11 of f/16. For variable aperture zoom lenses like yours the sweet spot will change as the maximum aperture, as you zoom in, changes. I suspect your lens will give you similar results. regardless of the camera you put it on.
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