Please, Can You Focus?

Discussion in 'Casual Photo Conversations' started by davidrosen, Feb 15, 2019.

  1. The subject is out of focus. DELETE. Gone forever (history is created the moment the shutter button is pressed). When I am in the midst of shooting pictures and suddenly I am consumed (and confused) with my camera's focus mode, I'm screwed. Cameras are not equal when it comes to focus technology. I do not begin to understand the technology - focus based on contrast, etc. My camera is not rated the BEST in focus, but I want to maximize its capabilities. And so, I must understand...FOCUS: Auto Focus Single (AFS) - Subject is still; Auto Focus Flexible (AFF) - Movement cannot be predicted; Auto Focus Continuous (AFC) - Subject is moving. Then there is Face/Eye Detection, Trackting, 49-Area, Custom Multi, 1-Area, Pinpoint. I KNOW! I can read the camera manual (over and over), and review the camera settings (over and over). But I am in the midst of taking pictures! Please share your thoughts.

    This is going to hurt:
    michaellinder likes this.
  2. David, because of my funky vision (despite my glasses), I use autofocus whenever possible. In certain situations when necessary, I use multi-point manual focus.
  3. Sandy Vongries

    Sandy Vongries Administrator Staff Member

    If your camera has a focus indicator light train yourself to keep an eye on it. Choose an F stop that gives greater depth of focus. If / when using manual focus, look for a detail with a sharp edge to use as a focus guide. Preset your camera for hyperfocal distance and adjust minimally on the fly as needed. I have found the various types of autofocus to be good, though unusual backgrounds and contrast ranges can be problematic.
  4. The tried-and-true method is "focus and re-compose." This worked for rangefinders (the only option), SLRs, most early DSLRs, and still works today, if your subject is relatively static. It is the best method for landscapes, and second-best for portraits.

    Designate a center spot focusing area, and single-servo focusing (AF-S). Place the spot on the part of the subject you want in focus, half-press the shutter release, then point the camera to finish the composition and shoot.

    If you need more flexibility, use a wider or expandable focusing area. The nearest object in that area will be in focus (even if it's a hand or piece of furniture, not the face).

    For portraits, AF with face-recognition or eye-focus is probably the best, with a flexible or moveable focusing spot.

    For action (including toddlers), continuous-servo (AF-C) is the best choice, with a wide-area or flexible focusing spot. If your camera has tracking and/or face recognition, you can use a smaller spot, and the camera will track the selected subject throughout the frame. You can use it for a pseudo-focus-and-recompose strategy, but it's not as reliable as the old-fashioned method.

    For landscapes and static subjects, I often use a hybrid method, called DMF by Sony. After AF locks on the subject, manual focus is enabled. You can re-focus to taste at that point. That said, for many subjects, including action, I use a manual focus lens. I made my bones with a Leica from the 60's until the late 90's, and old habits die hard. AF is about 3x quicker, and not to be ignored.
    sjmurray and davidrosen like this.
  5. Given the complexities and capabilities of modern AF cameras, I think it would make sense to post this question in the equipment forum that matches the brand camera that you are using and specify the model (and lense) plus the types of subjects that you typically shoot or have been having trouble getting reliable focus. My specific experience with Canon EOS and Olympus M43 may not be particularly helpful to you.
    davidrosen and Sandy Vongries like this.
  6. Autofocus is a tool. Tools require learning how to use them, even when they are "automatic".

    In this case, knowledge of how the AF actually works physically may not be all that important, but here is a summary of the early AF systems:
    Almost all surviving AF systems use a Honeywell variant.
    davidrosen likes this.
  7. :)

    Everyone who engages in a craft, from Cartier Bresson to Arthur Rubinstein, practices. Great advice already provided here and your manuals will be helpful, too. Set yourself some practice time when you’re not concerned with getting a good shot and more concerned with learning what you can. Chances are you will learn a bunch and I wouldn’t be surprised if you came away with some good shots even from a practice session.
    ken_kuzenski and davidrosen like this.
  8. Focus and re-compose - I keep forgetting to do that. Thanks for the reminder.
  9. Basically, I don't trust my camera to make decisions for me. So I pretty much always use 'point focus'. As @Ed_Ingold says, you can recompose your shot with the same focus point. Your Aperture will determine your DOF. With 'automatic' focus modes, it's just possible that your camera is still 'searching' for an optimal focus point when you take the shot. It's also possible that in some focus modes your camera can't decide on an 'optimal focus point' and just keeps refocusing on different points when you're taking the shot. I have have no real understanding of this, just guessing. In any case, if you really want to take personal control over your focus points, I would advise against using your camera's 'automatic focus' modes (except for maybe group shots). Your lens AF is different. Yes, you can manually focus but a lens with AF is usually much faster and easier to work with.

    As a last point, I wouldn't personally delete your photo. Not all photos need to be sharply focused. It looks OK to me. There are even PP techniques (like a high-pass filter) that can add some sharpness where you want it.
    davidrosen likes this.
  10. "Basically, I don't trust my camera to make decisions for me" Mike.

    Zone focus, manual focus, when it is important. How many times do we miss when auto focus, autofocuses, on something and nothing?
    mikemorrell likes this.
  11. The two main mechanisms of auto focus are phase difference and contrast. The former is a stereoscopic method which determines both the distance and direction of the correct focal plane. The second looks for edge contrast, and seeks to maximize it. The first is directional and determinant, the second is basically trial and error. For the STEM inclined, it is the difference between Newtonian and binary search methods. Phase difference is ineffective at relative apertures smaller than f/5.6. Contrast is generally effective, but slower and tends to hunt, especially at small apertures and low light. Most systems are hybrid, where phase difference will move the focus to a calculated position in milliseconds, then fine tune the results with contrast detection. Neither method works where there is little or no visible detail.

    The Sony A9 is arguably the most sophisticated focusing machine on the market. It is blindingly fast if set up properly, and a head-banger if not. Every camera and system is different, and some lenses work better than others. You have to know your tools before you start building cabinets.

    Sometimes it's back to basics. I use focus-and-compose at least 80% of the time because it always works (tangent effect notwithstanding). The next stage is to move the focusing bracket off-center, so I don't have to continually move the camera. Every other technique is on an as-needed basis. I'm still learning (after only 60 years), and open to suggestions.
  12. Well, we do not take photographs to become astronauts. A camera getting in one's shooting in such a way is a real pain and nothing can soothe the anxiety inside the digital sector. A rangefinder or a split-image screen would help, but that's another story.
  13. I have always relied on manual focus. When AF came out 30 years ago and I realized how many errors it made, I gave up on the idea. My attitude was "what is the sense in focusing and then re-composing, I thought this was supposed to be AF." I do have one AF lens and after reading this I may actually give it a shot. I also want absolute certainty that the camera is not going to shift focus after I recompose.

    Not all out-of-focus photos are focused incorrectly. They may be subject to camera movement as well. If IS/VR is available then you can use this to attempt to overcome the problem. I use a tripod as much as I possibly can when sharpness is critical. When handholding your camera try to set the shutter speed at 1/focal length of the lens you are using, or faster. So, if you are using a 70-200mm zoom lens set at 100mm focal length use a shutter speed of 1/90 to 1/125 or faster like 1/250. Even VR/IS will only get you down to the 1/15 to 1/30 range, in this example. Then at 1/15 is the worst speed for introducing mirror slap vibration. So many cameras offer mirror lock up which is really only useful when using a tripod.

    My impression is that not only is your photo out of focus but that there is camera movement there too.
  14. You don't think stopping to manually focus a camera "gets in the way"?

    Modern photography is 90% craft and 10% art. Once learned, the first becomes subconscious, so you can concentrate on the latter.
  15. This overview article on automatic focus modes and performance in Photography Life is perhaps worth reading. It's not too technical and, I think, more easily readable than most camera manuals. It explains in different words some of the topics that @Ed_Ingold's and @JDMvW have already mentioned.

    @davidrosen, I don't mean this to be in any way condescending (or insulting!) to your photography skills, but I've found that pretty much all of my own out-of-focus shots are down to me and not the AF mode. Occasionally, I forget to check which mode AFS/AFC I'm in. But by far the biggest cause of my out-of-focus shots is that - in the 'midst of taking pictures' - I see something and too quickly 'point and click' without giving the AF system enough time to re-focus (given the lighing/contrast conditions). Slowing down a fraction (making sure I first half-depress the shutter or use a back-button, see a sharply focused image in the viewerfinder and only then fully depress the shutter) has reduced the number of my out-of-focus shots, especially in poor lighting conditions.

    Understanding and choosing the right AF mode/area is necessary. I personally only use a couple of basic AF modes. It took me a while to learn from experience (sport/action/event shots) that I didn't always give my AF - in whatever mode - enough time to work (re-focus). Maybe this has no relevance for you, but it's worth considering.
    davidrosen likes this.
  16. I still use the focus and recompose method from the old days of shooting SLR's. I have to be careful about exposure though as it could change. SO then I have to set the exposure first. I also use the changing exposure as I move around my camera to get the exposure setting rather than offsetting the exposure using a dial. Quicker that way.
  17. Can I put in a plug for "back button focus"? If one does not already use it, then there are a lot of good articles describing the how's and why's. It has become my go-to mode, combined with single point focus, for absolute control over what my camera is using its high-tech to accomplish. Depending on the camera system this provides a number of advantages. For my Nikon system, I have continuous focus for as long as I keep the "focus on" button pressed, but the focus locks immediately I release the button. By using the single focus point I know precisely where the camera is focused (for slow and static subjects). And, by disconnecting the AF system from the shutter release the camera does not try to re-focus every time I make an image, thus avoiding the potential errors/variations/delays which occur with every re-focus operation. It takes some work to develop the muscle memory, but I feel it is more than worth it.
    mikemorrell likes this.
  18. Looking on the picture, it's hard to tell if it's out of focus or motion blur. Usually autofocus error, it's when camera choosing to focus on wrong place, but everything out of focus on the posted picture.
  19. I am 60 years old, so my eyesight is not as good as it ounce was, but......what IS in focus in that picture.?
  20. What's wrong with stopping in order to take a picture?
    John Crowe and Vincent Peri like this.

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