Hey, all, I am a newbie on this forum -- been enjoying the digest for a while. My question is whether I am the only one who has persistent focus issues with long 'big glass' (in my case 500mm f4, Nikon, but I have a friend who complained of the same kind of issue with his Canon 500mm f4). The problem is that if the subject (usually an animal) is around 1/10th of the frame, the single-point autofocus yields a frustrating fraction of images focused on the background behind the animal. Often this renders the image useless. This is especially the case when the background is more contrasty or complex than the subject (e.g., mammals against grass, ducks against water). It happens no matter how careful I try to be with the placement of the focus point (avoiding, if possible, having ANY part of the indicated square fall outside the main subject). It is usually NOT a problem if the background is less complex than the subject (e.g., flying birds against the sky). The problem is not a fine-adjustment issue, as the focus is perfect when the subject is considerably larger (like 1/4 of the image). I have tried to use the 'face detect' feature (although the Nikon version does not serve particularly well for animals) to encourage focus on the head, to no obvious benefit. It has occurred on at least five different models of Nikon DSLR (D3s, D4, D5, D500, D850). Can any of you explain what aspect of the autofocus system causes this behavior? Is there anything to be done about it other than checking the shot and retaking it if possible? Many thanks for your input!
chjaddbs wrote:
Hey, all, I am a newbie on this forum -- been enjoying the digest for a while. My question is whether I am the only one who has persistent focus issues with long 'big glass' (in my case 500mm f4, Nikon, but I have a friend who complained of the same kind of issue with his Canon 500mm f4). The problem is that if the subject (usually an animal) is around 1/10th of the frame, the single-point autofocus yields a frustrating fraction of images focused on the background behind the animal. Often this renders the image useless. This is especially the case when the background is more contrasty or complex than the subject (e.g., mammals against grass, ducks against water). It happens no matter how careful I try to be with the placement of the focus point (avoiding, if possible, having ANY part of the indicated square fall outside the main subject). It is usually NOT a problem if the background is less complex than the subject (e.g., flying birds against the sky). The problem is not a fine-adjustment issue, as the focus is perfect when the subject is considerably larger (like 1/4 of the image). I have tried to use the 'face detect' feature (although the Nikon version does not serve particularly well for animals) to encourage focus on the head, to no obvious benefit. It has occurred on at least five different models of Nikon DSLR (D3s, D4, D5, D500, D850). Can any of you explain what aspect of the autofocus system causes this behavior? Is there anything to be done about it other than checking the shot and retaking it if possible? Many thanks for your input!
Hey, all, I am a newbie on this forum -- been enjo... (
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A couple thoughts: How about using several points instead of a single point to focus? Also, are you shooting multi-shot? Handheld? Is the point jumping during shooting? Maybe try a tripod and single shot. What is your shutter speed? If high, try shutting off VR (if on)
Thanks for your thoughts and questions... the problem is worse with 9- or 25- point focus mode, which is why I use single-point mode most of the time. I do shoot in bursts, and there is the expected slight loss of focus for fast-moving animals when I use the highest burst rate (the camera does not refocus between frames) -- but if the focus starts out on the background, it never 'jumps' to the animal, sadly. I mostly shoot on a tripod. The problem MAY be worse at faster shutter speeds, but that may be just because I have less time to compose carefully (the focus square may get toward the edge of the subject more often, but I REALLY try to keep it inside). I use VR only at shutter speeds slower than 1/400th of a second (and then not always, especially if the lens does not need to move, like if I am set up on a nest or den). If I forget and use it at faster shutter speeds, the result is not a consistent focus shift but rather a weird edge softness that is ugly but somewhat correctable in post-processing (but really would rather avoid it!). I have not tried to replicate this problem, and perhaps I should do so, under controlled conditions -- I do wonder if there is any simple camera setting 'fix' that I have not tried or heard of.
chjaddbs wrote:
Hey, all, I am a newbie on this forum -- been enjoying the digest for a while. My question is whether I am the only one who has persistent focus issues with long 'big glass' (in my case 500mm f4, Nikon, but I have a friend who complained of the same kind of issue with his Canon 500mm f4). The problem is that if the subject (usually an animal) is around 1/10th of the frame, the single-point autofocus yields a frustrating fraction of images focused on the background behind the animal. Often this renders the image useless. This is especially the case when the background is more contrasty or complex than the subject (e.g., mammals against grass, ducks against water). It happens no matter how careful I try to be with the placement of the focus point (avoiding, if possible, having ANY part of the indicated square fall outside the main subject). It is usually NOT a problem if the background is less complex than the subject (e.g., flying birds against the sky). The problem is not a fine-adjustment issue, as the focus is perfect when the subject is considerably larger (like 1/4 of the image). I have tried to use the 'face detect' feature (although the Nikon version does not serve particularly well for animals) to encourage focus on the head, to no obvious benefit. It has occurred on at least five different models of Nikon DSLR (D3s, D4, D5, D500, D850). Can any of you explain what aspect of the autofocus system causes this behavior? Is there anything to be done about it other than checking the shot and retaking it if possible? Many thanks for your input!
Hey, all, I am a newbie on this forum -- been enjo... (
show quote)
If you are using AF-S mode have you used Nikon ViewNX to see where it indicates the focus point used was? It may give some clues.
Steve Perry as a book on this, and I found (but misplaced) a link to a short description of the Nikon focussing system. I think that you will find that the focusing area is significantly larger than the square that you see in your viewfinder, and as you have noted, the effect is worse with a larger number of focus points.
Kozan
Loc: Trenton Tennessee
chjaddbs wrote:
Hey, all, I am a newbie on this forum -- been enjoying the digest for a while. My question is whether I am the only one who has persistent focus issues with long 'big glass' (in my case 500mm f4, Nikon, but I have a friend who complained of the same kind of issue with his Canon 500mm f4). The problem is that if the subject (usually an animal) is around 1/10th of the frame, the single-point autofocus yields a frustrating fraction of images focused on the background behind the animal. Often this renders the image useless. This is especially the case when the background is more contrasty or complex than the subject (e.g., mammals against grass, ducks against water). It happens no matter how careful I try to be with the placement of the focus point (avoiding, if possible, having ANY part of the indicated square fall outside the main subject). It is usually NOT a problem if the background is less complex than the subject (e.g., flying birds against the sky). The problem is not a fine-adjustment issue, as the focus is perfect when the subject is considerably larger (like 1/4 of the image). I have tried to use the 'face detect' feature (although the Nikon version does not serve particularly well for animals) to encourage focus on the head, to no obvious benefit. It has occurred on at least five different models of Nikon DSLR (D3s, D4, D5, D500, D850). Can any of you explain what aspect of the autofocus system causes this behavior? Is there anything to be done about it other than checking the shot and retaking it if possible? Many thanks for your input!
Hey, all, I am a newbie on this forum -- been enjo... (
show quote)
Firstly, make sure you are using spot focus mode. If then, the camera can focus outside your intended area. The area that can capture focus goes beyond the little square in the middle of the screen. Steve Perry has a great video on spot focusing at
https://backcountrygallery.com/spot-metering-crash-course/ Check it out.
In the long run, you just may have to get closer to your subject. Or use manual focus.
Gene51
Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)
chjaddbs wrote:
Hey, all, I am a newbie on this forum -- been enjoying the digest for a while. My question is whether I am the only one who has persistent focus issues with long 'big glass' (in my case 500mm f4, Nikon, but I have a friend who complained of the same kind of issue with his Canon 500mm f4). The problem is that if the subject (usually an animal) is around 1/10th of the frame, the single-point autofocus yields a frustrating fraction of images focused on the background behind the animal. Often this renders the image useless. This is especially the case when the background is more contrasty or complex than the subject (e.g., mammals against grass, ducks against water). It happens no matter how careful I try to be with the placement of the focus point (avoiding, if possible, having ANY part of the indicated square fall outside the main subject). It is usually NOT a problem if the background is less complex than the subject (e.g., flying birds against the sky). The problem is not a fine-adjustment issue, as the focus is perfect when the subject is considerably larger (like 1/4 of the image). I have tried to use the 'face detect' feature (although the Nikon version does not serve particularly well for animals) to encourage focus on the head, to no obvious benefit. It has occurred on at least five different models of Nikon DSLR (D3s, D4, D5, D500, D850). Can any of you explain what aspect of the autofocus system causes this behavior? Is there anything to be done about it other than checking the shot and retaking it if possible? Many thanks for your input!
Hey, all, I am a newbie on this forum -- been enjo... (
show quote)
It is a fact of life. If the "thing" you are trying to focus on is too small, the AF point sensor won't see it. This is where practice and manual assist focusing come into play. It will get better but you'll have to experiment with your AF settings, and try to get closer to your subjects. And do expect to have around a 80%-90% discard rate on images - mostly due to camera/subject movement causing blur, focus errors, and the occasional exposure error. It does get better over time and with lots of practice.
Focus isn’t easy as it sounds when you don’t know how and what settings. I had the same problem for a long time. Jason Odell and Steve Perry helped me to learn the focus system. Actually I used Jason Odell birding lesson And settings (focus, suttterspeed ISO....)
How far away are you from the subject? At surprising shorter distance atmospherics come into play. Even engine heat can cause distortion when shooting from your seat in the truck or car.
chjaddbs wrote:
Hey, all, I am a newbie on this forum -- been enjoying the digest for a while. My question is whether I am the only one who has persistent focus issues with long 'big glass' (in my case 500mm f4, Nikon, but I have a friend who complained of the same kind of issue with his Canon 500mm f4). The problem is that if the subject (usually an animal) is around 1/10th of the frame, the single-point autofocus yields a frustrating fraction of images focused on the background behind the animal. Often this renders the image useless. This is especially the case when the background is more contrasty or complex than the subject (e.g., mammals against grass, ducks against water). It happens no matter how careful I try to be with the placement of the focus point (avoiding, if possible, having ANY part of the indicated square fall outside the main subject). It is usually NOT a problem if the background is less complex than the subject (e.g., flying birds against the sky). The problem is not a fine-adjustment issue, as the focus is perfect when the subject is considerably larger (like 1/4 of the image). I have tried to use the 'face detect' feature (although the Nikon version does not serve particularly well for animals) to encourage focus on the head, to no obvious benefit. It has occurred on at least five different models of Nikon DSLR (D3s, D4, D5, D500, D850). Can any of you explain what aspect of the autofocus system causes this behavior? Is there anything to be done about it other than checking the shot and retaking it if possible? Many thanks for your input!
Hey, all, I am a newbie on this forum -- been enjo... (
show quote)
First welcome to the forum, One of the contributors to this site is Steve Perry, an independent & very knowledgeable Nikon person. Note, Independent. ..He has tested almost every lens & Nikon body as well as authoring numerous ebooks on focus. If you go to his site :BackCountryGallery...He has an E~Book you can download for a nominal fee ""Deep Focus Techniques" which describes much of what you seem to be encountering (HyperFocal Distance) & how to best figure it. If this is not the case, my apologies.
chjaddbs wrote:
Hey, all, I am a newbie on this forum -- been enjoying the digest for a while. My question is whether I am the only one who has persistent focus issues with long 'big glass' (in my case 500mm f4, Nikon, but I have a friend who complained of the same kind of issue with his Canon 500mm f4). The problem is that if the subject (usually an animal) is around 1/10th of the frame, the single-point autofocus yields a frustrating fraction of images focused on the background behind the animal. Often this renders the image useless. This is especially the case when the background is more contrasty or complex than the subject (e.g., mammals against grass, ducks against water). It happens no matter how careful I try to be with the placement of the focus point (avoiding, if possible, having ANY part of the indicated square fall outside the main subject). It is usually NOT a problem if the background is less complex than the subject (e.g., flying birds against the sky). The problem is not a fine-adjustment issue, as the focus is perfect when the subject is considerably larger (like 1/4 of the image). I have tried to use the 'face detect' feature (although the Nikon version does not serve particularly well for animals) to encourage focus on the head, to no obvious benefit. It has occurred on at least five different models of Nikon DSLR (D3s, D4, D5, D500, D850). Can any of you explain what aspect of the autofocus system causes this behavior? Is there anything to be done about it other than checking the shot and retaking it if possible? Many thanks for your input!
Hey, all, I am a newbie on this forum -- been enjo... (
show quote)
Someone will take issue with this I know but do you use back button focus?
The problem you describe could be caused by using auto focus. Letting the camera decide the subject of the photograph could cause this issue. Manual focus will work a bit better for this.
--Bob
chjaddbs wrote:
Hey, all, I am a newbie on this forum -- been enjoying the digest for a while. My question is whether I am the only one who has persistent focus issues with long 'big glass' (in my case 500mm f4, Nikon, but I have a friend who complained of the same kind of issue with his Canon 500mm f4). The problem is that if the subject (usually an animal) is around 1/10th of the frame, the single-point autofocus yields a frustrating fraction of images focused on the background behind the animal. Often this renders the image useless. This is especially the case when the background is more contrasty or complex than the subject (e.g., mammals against grass, ducks against water). It happens no matter how careful I try to be with the placement of the focus point (avoiding, if possible, having ANY part of the indicated square fall outside the main subject). It is usually NOT a problem if the background is less complex than the subject (e.g., flying birds against the sky). The problem is not a fine-adjustment issue, as the focus is perfect when the subject is considerably larger (like 1/4 of the image). I have tried to use the 'face detect' feature (although the Nikon version does not serve particularly well for animals) to encourage focus on the head, to no obvious benefit. It has occurred on at least five different models of Nikon DSLR (D3s, D4, D5, D500, D850). Can any of you explain what aspect of the autofocus system causes this behavior? Is there anything to be done about it other than checking the shot and retaking it if possible? Many thanks for your input!
Hey, all, I am a newbie on this forum -- been enjo... (
show quote)
billnikon
Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont
chjaddbs wrote:
Hey, all, I am a newbie on this forum -- been enjoying the digest for a while. My question is whether I am the only one who has persistent focus issues with long 'big glass' (in my case 500mm f4, Nikon, but I have a friend who complained of the same kind of issue with his Canon 500mm f4). The problem is that if the subject (usually an animal) is around 1/10th of the frame, the single-point autofocus yields a frustrating fraction of images focused on the background behind the animal. Often this renders the image useless. This is especially the case when the background is more contrasty or complex than the subject (e.g., mammals against grass, ducks against water). It happens no matter how careful I try to be with the placement of the focus point (avoiding, if possible, having ANY part of the indicated square fall outside the main subject). It is usually NOT a problem if the background is less complex than the subject (e.g., flying birds against the sky). The problem is not a fine-adjustment issue, as the focus is perfect when the subject is considerably larger (like 1/4 of the image). I have tried to use the 'face detect' feature (although the Nikon version does not serve particularly well for animals) to encourage focus on the head, to no obvious benefit. It has occurred on at least five different models of Nikon DSLR (D3s, D4, D5, D500, D850). Can any of you explain what aspect of the autofocus system causes this behavior? Is there anything to be done about it other than checking the shot and retaking it if possible? Many thanks for your input!
Hey, all, I am a newbie on this forum -- been enjo... (
show quote)
Oh grasshopper, your focus issues will not improve until you are closer.
The D5 however has a system on enlarging the image and putting a painted surface on the subject that shows exactly what is in focus. See Steve Perry's book of Nikon focusing for an explanation of this.
Ourspolair wrote:
Steve Perry as a book on this, and I found (but misplaced) a link to a short description of the Nikon focussing system. I think that you will find that the focusing area is significantly larger than the square that you see in your viewfinder, and as you have noted, the effect is worse with a larger number of focus points.
He just put out a u-tube vid on this. I’m on my tablet or I would include the link.
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