Blurry pictures with large DOF?

[jen_demaro]

<p>Hello there! <br>

I am a portrait photographer. I have no issues with pictures with a short DOF...everything is crisp and in focus. However..when I attempt to do a picture with a large DOF..for example like a couple in a field far away..the couple is not in focus. Often things around the couple like the field or background maybe more in focus than the couple itself. <br>

I keep the focus point right directly on the couple and I do not move my camera at all when I take the picture. I am wondering if its either 1. I need to invest in higher grade prime lenses 2. It is something I am doing wrong with my settings. I usually shoot wide open if I can but I am wondering if I need adjust that for this type of picture. <br>

The two primes that I have been using are 50 mm 1.8 and 35 mm 2.0. I'm definitely looking to upgrade one if not both of these in the near future. <br>

Thank you so much! Thank you for your friendly responses. </p>

[jamie_robertson2]

<p>My first guess is that you may need to calibrate the lenses to your camera if the DSLR you are using has the micro focus adjustment option. Failing that, it could be worth sending the whole lot in for calibration if it's of major concern.</p>

[Matt Laur]

<p>If you're stopping the lens down past, say, f/11 ... you're going to get visible softness from diffraction. That's a laws of physics thing. Better to use the hyperfocal distance to get what you want in focus than to go for max DoF by stopping down too far and suffering diffraction.<br /><br />And, of course, Jamie is right - if you aren't calibrated correctly, all bets are off. Does this happen even when manually focusing with live view on the LCD display?</p>

[pmind]

<p>If you post an example, it may help us figure out what's going on.</p>

[JeffOwen]

<p>I have the same issue when I use a single central point to focus with. Then this point focuses between the two subjects to an object in the distant behind. The only way round is to ensure either that the focus is just to one side to pick up one of the subjects or to use more focus points in the camera.</p>

[paddler4]

<p>It would be helpful if you posted an example, with exif data and with an indication of the focus points.</p>

<p>Unless the calibration is WAY off or you are shooting at extremely small apertures, my guess is that the issue is focusing technique. I disagree with Matt--I doubt you will have much of an issue with diffraction unless you are going much smaller (larger f stop) than f/11. However, you can easily test this for yourself. In a well lit setting, put your camera on a tripod, set it for aperture priority, focus on something like a brick wall (so all focus points are hitting the same plane), and then take a series of pictures starting at f/5.6 and increasing by one stop between shots. That will show you the aperture at which diffraction is a problem for you.</p>

[jen_demaro]

<p> <img src=" " alt="" /><br>

Here is an example of what I am talking about (for some reason it's not letting me load it as a picture). I had my focus point on the couple but the tree next to the couple is much more in focus than the couple itself. I do realize that the tree is slightly in front of the couple which could make a difference..however this same thing happens when they are on the same DOF and even when the background is behind the couple. <br>

I did shoot this lower than f/11 by the way..I had it set at f/3.5. So that could be an issue as well. <br>

Thanks for all your help..I am looking into the different advice people have given</p>

[phule]

<p>It's nearly impossible to determine anything from the re-sized photo, Jen. Can you paste a link to a full sized photo?</p>

[dcstep]

<p>The focus seems to be way in front of the couple and you're shooting at f/3.5, resulting in shallow DOF on the grass. I'd suggest shooting in the f/8 to f/11 range and focus on the couple with a single AF point. If you had all the AF points on, the camera probably grabbed some of the grass in the foreground.</p>

[JAPster]

<p>One thing that might be going on here is that being a portrait photographer you are used to seeing the detail sharpness you get with a crisply focused subject at short range. At short range, or a shot made with a telephoto, the subject fills a majority of the viewfinder, say 70%. So if you make a facial portrait, and the subjects face fills 70% or more of the viewfinder, then many many many pixels are used to render the details in the subject face, and this results in much much better & sharper image resolution & clarity. Especially if the subject lighting is real good.</p>

<p>But in the type of shot you are discussing, the subjects are being placed far away from the camera to make a differnt type of picture. The normal & w/a primes you are using are not going to maginify the subjects in any way. So, in effect, the subjects themselves (bodies & faces) are going to be much smaller in the overall viewfinder frame. So when you make the shot, and the camera sensor captures the digital image of the whole frame, then the subjects look far more fuzzy & soft simply because a much much smaller number of pixels used to render the subjects in the image. </p>

<p>In either type shot, closeup facial or far-away in the field, the camera sensor will use exactly the same number of pixles (horizontal & vertical) to 'paint' the optic image created by your lens. But in the closeup shot many many many more dots form the subject, whereas in the far away shot, many many many less dots form the subject. So unless you use a lens that will zoom in & maginfy the subjects, as you place them farther & farther away from the camera, they will look smaller in the optic image, resulting in less digital resolution of the subject that will appear to be less sharp, less clear.</p>

[dcstep]

<p>Alan, if you look at her picture on Flickr at full-screen, you can see that the subjects are OOF. I think it's due to a combination of a focusing error and using too wide and aperture.</p>

[Matt Laur]

<p>Well, now that I see the image, I agree that this isn't a diffraction issue. Looks like the tree or the grass caught the focus, instead of that woman being attacked by the bear. :-)<br /><br />From the OP's description, I thought we were talking about the use of an aperture meant to produce <em>more</em> DoF, but not much should be expected at f/3.5, obviously.</p>

[devon_mccarroll]

Jen, I was thinking the same thing as Matt. A short DOF means shooting at wide apertures, like f 3.5--which will leave only a small

area in focus--and a large DOF would mean stopping your lens down, for instance f11 or f16, which puts more of the image in focus. So

I'm wondering if you understand the difference between DOF and subject distance? Those are two different things. And maybe you do

and I just didn't understand the way you worded it. Was your reason for shooting with such a shallow DOF to have only the couple in

focus and everything around them not as sharp?

[brad_trostad]

<p>Are you setup to use the center focus point only?</p>

<p>Are either of the servo modes enabled?</p>

<p>Are you using the mode on the mode dial (unique to Canon) that has to do with the camera setting the Aperture to get all the focus points in focus?</p>

<p>Does this only happen with one lens?</p>

<p>Does this lens give the same problem on someone else's camera?</p>

<p>If you have live view, can you set to manual focus, zoom 10x, focus on the subject and get the shot you are after? (Not for normal use, just to verify the camera will be in ficus the desired distance when overriden).</p>

 

<p>If none of those are getting in your way then do a quick lens focus test (shoot shallow DoF at an angled target and get a fee for front / back focus.</p>

<p> </p>

[model mayhem gallery]

<p>I have both of those lens and they are great and I don't think an upgrade is needed for either. However, I had the exact same problem until I realized 2 things.<br>

1. You really can't shoot wide open at 1.8 or "shorter\larger" and get sharp images without a tripod. Any little movements ever so slight by you or the subject will cause out of focus issues.<br>

2. I always use manual focus when shooting apertures largre than F2.8. You can not depend on the camera to know what you want to be sharp only your eye can do this espeacially at F2.0 of F1.8.<br>

3. Trick of the trade... With camera on tripod use live view to zoom in 100% and manually focus to get super sharp focus. This is only Live View Zoom not actually zooming the lens. Once you have sharp focus on say eyes then take the shot. Autofocus will be hit and miss and generaly not get details right at larger apertures.<br>

Its like shooting a rifle a 1000 yards if everything is not perfect encluding your form and supports you will be way off.</p>

[stephen_mcpherson]

<p>Jen, DOF has 3 major variables: aperture, focal length and distance from the subject. In your case you choose to use a large aperture (shooting wide open) which in turn makes the DOF significantly more shallow. You also used a moderate focal length (50mm) that would tend to be DOF neutral. Also your distance to the subject was moderate so that would be DOF neutral. Therefore your aperture setting is causing you to have a very shallow DOF, i.e., almost everything in the frame is fuzzy. In a situation like you were shooting, you might want to try f8 or f11. That would sharpen the image significantly. </p>

[kirigoi]

<p>In response to <a href="/photodb/user?user_id=1063650">M. P.</a> above, I have to disagree with all 3 of your "2 things".</p>

<p>1: "You can't shoot wider than 1.8 without a tripod": This is patently false, and refuted by photographers daily. Although focussing can be challenging, a tripod only helps with your own movement, not the subject's. Important tips to help are choosing an appropriate focus point (i.e. avoiding the focus/recompose method), having a stable shooting position, and not hesitating too long between focussing and releasing the shutter. The OP has not given too much info about the picture he posted, only specifying he used f/3.5, but I'll take a worst case scenario using a DOF calculator like <a href="http://www.dofmaster.com/dofjs.html">this</a>, and assume a full frame camera, 50mm lens at f/1.8, and a subject distance of 20 feet (a substantial underestimate I believe). If correctly focussed at 20ft, for a circle of confusion of 0.03mm everything would be in focus from 17.7-23ft, meaning he's got over 5 feet to play with. Any subtle movements should not cause appreciable focus errors. There are far more challenging conditions, such as handheld closeup portraits using faster glass, or even more challenging; macro shots at high magnification (where your tripod suggestion starts to becomes appropriate).</p>

<p>2. "You should focus manually for apertures larger than f/2.8". This is a dangerous suggestion as the ground glass on most modern cameras is set to give a bright image, and simply isn't intended for accurate manual focussing at large apertures. I won't say it can't be done but it is very challenging. I came from a film background where we had manual focussing aids such as micro-prisms and split image viewfinders, but my hit-rate at wide apertures is still<strong> far</strong> faster using modern autofocus systems.</p>

<p>3."Use live view at 100% to manually focus" This is actually a good tip; live view is free of the risk of front/back focussing that can affect poorly configured phase-detect systems. I'd thoroughly recommend it for getting critical focus in landscapes/still life type photography. The same thing can help autofocussing though; contrast detect focussing using live view is also extremely accurate, and as long as the focus point is correctly positioned should not be hit and miss like you suggest.</p>

<p>I believe the OP's focussing problems are more likely to lie with either poor focussing technique, unfamiliarity with his kit, or possibly a fault with his camera or lens (such as needing micro focus adjustment). The posted photo was not an example of challenging focus, so there's something else going on and with a bit more information about his technique we should be able to work out what; <a href="/photodb/user?user_id=6509906">Brad Trostad</a>'s suggestions are a very good start. However, no matter how well intentioned, incorrect suggestions about how to solve his problem will not improve matters and will only result in confusion and worse technique.</p>

<p>To prove a point; here's two photos from a shoot last weekend. Shot using an 85mm lens at f/1.2. Handheld. Using autofocus. No matter their other merits, the focus in these photos is at least in the ballpark.<br /> <img src="http://www.skylight3d.com/images/photoNet/focus_small.jpg" alt="" width="600" height="450" /></p>

[kirigoi]

<p>And to reply directly to Jen, you need to be more careful with the terminology you have used. For example, I suspect larger DOF / smaller DOF means the opposite to what you think, and you can't refer to two objects being "on the same DOF" so much as in the same plane of focus.</p>

<p>The lenses you have are excellent performers. There are admittedly better lenses out there, at a much larger price point, but they have essentially the same focussing behaviour, and will most likely be even harder to focus if they have larger maximum apertures. </p>

<p>Although it is possible there are problems with the kit you are using, the way you expressed yourself makes me suspect it is more likely to be user error on your end, and is a source of a lot of the confusion in people's replies. Several people have made excellent suggestions so I'd suggest reading them through. I'd also recommend making sure the focus point you use is correctly placed over your subject, focus has locked, and you're not using one of the automatic focussing modes as that may be choosing different areas to what you may be expecting. Read your camera manual carefully and practice lots. Everyone gets a few out of focus shots, particularly when starting out, the benefit of digital is that you can check to see if you're getting the results you expect.</p>

<p>If you have more specific questions ask away, it would be good to see higher quality versions of the photos you are having issues with; you can always put them directly into your photo.net portfolio and direct us to them if you are having problems with uploads.</p>

<p>All the best, Mark</p>