5D3 sharper images when using manual exposure (allegedly!)
- Thread starter GuyF
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Thanks for all the comments.
Got further info from my colleague today - sticks to ISO 400 unless it's really bad light. Keeps shutter speed at 1/800th or faster. Reason for using Av and f2.8 was to ensure max isolation of subject from background - he wants to separate the player(s) on the ball from the distracting background of others on the pitch.
I suggested that the improved sharpness is simply a case of him having used smaller apertures without consciously realising at the time. I also pointed out the changing sharpness depending on where in the zoom range he is (including the changing DOF for a given aperture and distance to subject).
I've had to AFMA all my gear but he claims his lens doesn't need it. Hmmm, it could happen....
Thanks again.
Got further info from my colleague today - sticks to ISO 400 unless it's really bad light. Keeps shutter speed at 1/800th or faster. Reason for using Av and f2.8 was to ensure max isolation of subject from background - he wants to separate the player(s) on the ball from the distracting background of others on the pitch.
I suggested that the improved sharpness is simply a case of him having used smaller apertures without consciously realising at the time. I also pointed out the changing sharpness depending on where in the zoom range he is (including the changing DOF for a given aperture and distance to subject).
I've had to AFMA all my gear but he claims his lens doesn't need it. Hmmm, it could happen....
Thanks again.
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flowers
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I have no doubt some of the perceived sharpness came from using smaller apertures. I don't know about the specifics of zoom lenses other than that they tend to be softest at the extremes (a 70-200 would be softest at 0mm and at 200mm)GuyF said:
Actually, I think it sounds just as suspicious if you've had to afma ALL your gear. Are you sure your camera is okay or that your lens supplier isn't supplying you with lemons? I don't think it's normal that you don't get a single perfect lens. A big reason for buying high end lenses, among others, is that they tend to be better calibrated in the factory and the tolerances for quality control are higher.GuyF said:
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I guess I'm confused by both comments - first of all "had to AFMA all my gear" - we lived without AFMA for a while and were okay, so I don't think it has to be done. On the other hand, I have chosen to AFMA all of my lenses and all but one of them were in the +2 to +5 range and one was +9. Keep in mind that all of my AF lenses are f/1.2 to 2.8 and I calibrated extenders as applicable, I think that's pretty good.flowers said:
To me that is more indicative of camera bodies that are slightly out of tolerance and lenses vs. having lemons, especially the f/1.4 and f/1.2 lenses.
The only lenses I've ever had that were at "0" were my 400 f/5.6 and my 70-200 f/4 IS, which is more a result of their aperture vs. some level of exceptional quality. Obviously Canon provided this capability because their manufacturing tolerances aren't tight enough to give a "0" for every lens/body combination out there, so I certainly wouldn't consider a lens a "lemon" if it needs some AFMA. I had a 135 f/2 that was beyond +20, so I sent it to Canon and they corrected the optical alignment, but it was still a +2 afterwards.
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mackguyver said:
+1, to get optimal sharpness with a lens/camera combo, it almost always needs a +/- afma value. I've owned 5-6 bodies and 30+ lenses and only one copy of two lenses where no afma needed, and only on one body. If you have 6-7 lenses on one or two bodies, and claim none of them combos need afma, I dare say you are not doing the calibration well enough, or simply, happy with the slightly off results.
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flowers
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This is certainly possible! I don't know to what accuracy you measure the results. I am happy if the AF works very well for practical results. I admit I don't measure if it works down to the last millimeter but if I focus on the eye and the eye is in focus I don't try to see if the focus is 0.5mm in front of or behind the eye if the eye is not blurry and not defocused, especially since I post process all my images. Sharpened/edge sharpened OOF area looks BAD. If you do your PP and it looks good (sharp, focused) then I don't think there's a difference if it's the tiniest bit off, if you can't see it in the final result (in practice).Viggo said:
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flowers said:
Yes it depends on how much one care, I for one do not pay huge amounts of money to settle for sharp enough, when a little afma makes them the way they should be sharp like tack.
The best and most accurate way to do it, by far, is FoCal.
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Agreed and with most lenses, the difference is subtle, but the f/1.2 lenses show considerable differences in just a plus or minus 2 adjustments.Viggo said:
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I didn't get a 300mm f2.8 IS mk1 and 500mm f4 mk2 (amongst others) for shots to be "slightly off". If I feel tweaking the AMFA by +1 or -9 or whatever is necessary to get razor sharp results then I'm fine with that.
Other people can settle for less if they want.
Other people can settle for less if they want.
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GuyF said:
Well, I have not read the entire thread, but there could be some truth to his story, problem is, he isn't giving you the whole story. Let's try to fill in the holes. There are three things that control exposure: Shutter, Aperture, ISO. None of these things are "neutral" in their impact to IQ, however. Shutter not only controls the duration of exposure, but also has an impact on the amount of motion blur. Aperture not only controls the quantity of light over time, but also depth of field. ISO not only controls the rate at which the image saturates, but can also exacerbate noise.
In an auto exposure mode, you control ONE of these things (or, in the case of M+Auto ISO, two). Lets say your friend used to use Tv. He could then control shutter, but aperture and ISO are arbitrary factors. Depending on the needs of the scene, even a lens that is sharp at f/2.8 may not be sharp in a deep enough field, so if your shooting in lower light, you may end up with images that are sharp...in an extremely thin depth around part of your subject. Additionally, you might find that your images are noisier than you might have been able to achieve if you had total control over your exposure settings.
Av mode is similar. Again, you control one factor out of the three, and shutter speed and ISO become arbitrary factors. If you stop down your aperture to achieve the proper depth of field, your shutter might automatically end up too low, increasing motion blur. If you need f/8 for the proper DOF, depending on the capabilities of your camera and how the custom functions are configured, you might end up with a shutter that is MUCH too low, rather than an increase in ISO. You might have a low-noise image, but now you also have blur from camera shake.
Now, before I move on, better cameras, like the 5D III and 1D line, often offer much more configurability with custom functions to guide the camera into making the kinds of choices you would more often, thereby reducing the chance that you might fall into one of the situations where the camera chooses wrong, and your IQ suffers as a result.
There IS an argument for using manual mode to achieve sharper results. When you control every aspect of your exposure, you are also controlling every aspect of IQ. YOU control the shutter speed, and therefor have total control over whether you get motion blur or not. YOU control the aperture, and therefor have total control over whether the entire thickness of your subject is within your DOF. YOU control ISO, and therefor have total control over noise levels.
If your friend was really referring to his ability to exactly choose, via instinct or that natural sense that accumulates along with experience, the right shutter speed, aperture, and ISO to maximize his IQ....then he is absolutely correct. You CAN get sharper images when using manual exposure. The kicker is that you have to have the skill to gauge all the various aspects of your scene and your exposure settings to actually set them right and achieve that maximum level of IQ.
Personally, I use manual exposure mode for my bird and wildlife photography. I used to use Av, but I then I learned a bunch of new things, and I became aware of how to use manual mode properly to maximize IQ, on the fly, without having to actively think about it all that much. It's a technique that kind of comes along with a certain level of experience I think. With birds, I eventually got a sense of what apertures with what lenses I needed to get the right amount of the bird in the DOF, and at what minimum shutter I needed to freeze the bird's motion. I learned the range of ISO settings within which noise was acceptable and controllable in post. You also learn how to use the exposure meter at the bottom of the VF to help you, along with the brightness of various background factors, to gauge what your exposure needs to be (where the marker on the exposure meter SHOULD be pointing in order for exposure to be "correct" for that scene).
Once you reach that point, you don't have to think as much about what your doing when it comes to exposure. You make quick, momentary judgments about where you think the exposure meter indicator should be, what DOF you need, roll some dials, and start taking shots. You also begin to understand that once you set your exposure for a given scene in known lighting, you don't need to change your exposure once it's set. Only when the lighting changes, or you change your scene (i.e. point your lens somewhere else) do you then have to recalculate and choose new settings...but again, that should all happen in a couple of seconds and be done before you really realize you did it.
So, your friend isn't wrong, he just wasn't telling you everything.
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"No Reason" is a mighty big place...a touch dogmatic?flowers said:
On a 1-Series you can turn off modes. Primarily I like to work either in Manual or Av, so the rest are disabled. So when I toggle the mode control, all I'll get is either M or Av.
Last night I shot a swimming & diving championship event at a major swim stadium. The light levels vary slightly from end top end of the main pool, and Av is perfect is this situation. To achieve max shutter speed, I'm locked on f/2.8. Only the ISO or exposure compensation get adjusted. Earlier in the week I shot the final dress rehearsal of a stage production of Shakespeare's Twelfth Night. Naturally the lighting was all over the shop, as it should be for a stage production. Av was perfect. Track & Field athletics? Av please, especially under lights at night. In fact, just about any dynamic shooting situation where there are either subtle or substantial lighting variations, Av works for me.
-pw (Av fanboy)
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I sometimes think there might be a misunderstanding of what AFMA is and why one would want to do it. If by some miracle all your lenses actually matched perfectly to your camera and needed 0 AFMA, there is a very good chance those same lenses might need some require some adjustment on a different (perfectly good) body and some different adjustments on a third (perfectly good) body.
The need for AFMA is not an indictment on the quality of the lens or the body, it is just an acknowledgement of the fact that the lenses and bodies are created separately. AFMA is just an attempt to allow us to form a "more perfect union" between our individual bodies and lenses
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To the Av vs Tv comments. I prefer to use Av for sports and birding, if I'm not shooting in M. I prefer to control my DOF and keep an eye on the shutter speed rather than the other way around. Both accomplish the same thing, just a preference.
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