Compact cameras with depth of field control

[stinshoff]

<p>My old Canon A720 is on its last legs so I'm looking for a new compact to replace it. Has technology improved to the point where some of the newer compacts actually allow one to control depth of field - either through larger sensors, faster lenes or whiz bang electronics - or am I just wishing for something that doesn't exist?</p>

[r.t. dowling]

<p>Technically, any compact camera that allows you to manually control the aperture would allow you to also control the depth of field to some extent. The problem with most compact cameras is that they have really small sensors and relatively slow lenses, which results in huge depth of field, even when using the widest available aperture. This problem is mitigated to some extent in high-end compacts that have somewhat larger sensors, along with fast (large aperture) lenses.</p>

<p>One recent compact camera that is particularly good in this regard is the Olympus XZ-1. It has a larger sensor than most compacts, and a very fast f/1.8-2.5 lens.</p>

<p>Check out the following page of DPReview's report on the XZ-1, and scroll down to the "depth-of-field and background blur" section:</p>

<p>http://www.dpreview.com/reviews/OlympusXZ1/page8.asp</p>

<p>As you can see, the background isn't as blurred as it would be with a full-frame DSLR and an f/1.4 lens... but it's at least as blurred (or perhaps slightly moreso) as the APS-C DSLR and kit lens they compared it to. Not bad, and definitely superior to most other compact cameras. It's also just a good camera overall -- DPReview gave it their Gold Award.</p>

[phule]

<p>[[Has technology improved to the point where some of the newer compacts actually allow one to control depth of field - either through larger sensors, faster lenes or whiz bang electronics - or am I just wishing for something that doesn't exist?]]</p>

<p>You're wishing for something that doesn't really exist. Point and shoot cameras == tiny sensors and very wide-angle lenses == lots of apparent DoF.<br>

<br />However, as R.T. points out, there have been recent changes in the higher-end market, with slightly larger sensors and faster lenses being re-introduced. Olympus XZ1, Samsung TL500, & Nikon P300 have f/1.8 lenses. Canon S95 and Panasonic LX5 both have f/2.0 lenses.</p>

<p>Also to consider: the mirror-less compact interchangeable lens cameras. Panasonic GF2, Olympus E-PL2, Sony NEX5, Samsung NX100 all offer much large sensors and far more control over DoF than a fixed-lens point and shoot.</p>

[dave_redmann]

<p>Most of the compact cameras have tiny sensors of "1/2.5-inch" or so. Those of the "1/1.7-inch" sensor class give a little less depth of field, but realistically, even a 1/1.7-inch sensor at f/2.8 gives you about the same depth of field as 35mm film or "full-frame" digital at about f/11, or a common DSLR with a 1.53x crop-factor at about f/7.</p>

<p>But we are starting to see fairly compact cameras with much larger sensors. Most but not all have interchangeable lenses. They are not cheap. But the Sony NEX-3 and NEX-5, the Panasonic and Olympus Micro Four-Thirds cameras, and the Sigma DP-1 and DP-2 are all worth a look.</p>

<p>All else being equal, the smaller the sensor, the more the depth of field at a given f-stop. The Olympus XZ-1 has a 1/1.63-inch sensor. At the wide end of its zoom range it will open to f/1.8 (at the long end, f/2.5). That would give you roughly the same depth of field as a 35mm or full-frame at f/6.3 or a NEX-3 or -5 at f/4. The Sigmas have somewhat smaller sensors than the Sonys, and the Panasonics and Olympuses have somewhat smaller sensors still.</p>

 

[bill_tuthill]

You'll actually get shallower DoF with one of the long-lens compacts than with the "fast" models that are really fast only at wide angle.

 

Running the numbers, with the Fuji F550EXR zoomed all the way out to 66mm, at 2 meters your DoF is 6 centimeters. The F550 lens is very good at the long end.

 

With the Olympus XZ-1 (fastest P&S model so far) zoomed all the way out to 24mm, at 2 meters your DoF is 21 centimeters. That's better than the short end, where DoF is 365 centimeters despite f/1.8 aperture.

[r.t. dowling]

<p>That is true about the Fuji F550 and similar cameras in that class... although if the goal is portraiture, you're going to have to stand pretty far away from your subject! 66mm on the F550 is equivalent to 360mm on film... somebody out there who is better with math than I am can probably figure out how many feet from the subject you'd have to be in order to get a head & shoulders shot at 360mm equivalent.</p>

<p>Neat camera, though. I wouldn't mind having one. But I'm also lusting after the Oly XZ-1.</p>

[dave_redmann]

<p><em>You'll actually get shallower DoF with one of the long-lens compacts than with the "fast" models that are really fast only at wide angle.</em></p>

<p>Not really, or at least not necessarily. Because the longer the lens you use, the farther away from the subject you have to get for a field of view of a particular size. Putting aside questions of what sort of angle of view / lens length is aesthetically 'best' for a given type of picture, you'll find that using a longer lens requires getting farther back from the subject, which increases the depth of field, so often you're not really improving.</p>

<p>Now it is worth remarking that the key question for a compact, or any camera / lens with avariable maximum aperture, is what is the maximum aperture <em>at the focal length you'll be using for a particular shot</em>. Obviously a lens that has a maximum aperture range of f/2.8 at the wide end and f/3.5 at the long end might well (all else being equal, which often it isn't) be a better choice than a lens that goes to f/2.4 at the wide end and f/5.6 at the long end. I seem to recall that some of the older Panasonic superzooms were f/2.8 or f/4 even at the long end.</p>

 

[stinshoff]

<p>Thanks for the repiles, guys. I pretty much suspected I was searching for something that defied the laws of optics.</p>

[bill_tuthill]

<p>Here's a capture from the F300EXR, same lens as the F550EXR, at 66mm (360mm crop equivalent):<br>

Is that hops?</p>

[dg1]

<p>Your post is timely because I've been thinking of bringing the same topic up. It seems to me that the small sensor compacts lack mostly in the ability to create a shallow depth of field,( whereas it invariably seems to be the issue of noise and noise reduction that seems to obsess everyone). If they offered DOF control they'd seriously increase their appeal to enthusiast photographers.</p>

<p>I've been hoping one of the more adventurous manufacters (Ricoh, Fujifilm, Panasonic..) might approach this through firmware like they've done to counter lens distortion and CA. With the tiny processors getting faster and faster it seems like someone would have devised an algorithm that could simulate the DOF of different focal lengths and apertures based on the distance the camera calculates the focus point to be at. Perhaps this is hugely more complicated than the other existing firmware lens corrections. </p>

<p>I believe there are some post processing software products that claim to do this, but I haven't tried any of them. I have done some work with creating oof backgrounds in PS but my patience runs out.</p>

<p>My current solution to small cameras and DOF is to use film with an Olympus XA. Otherwise I think one of the m4/3rds like E-PL2 or lumix GF-1/2 would offer the best digital option.</p>

 

[stinshoff]

<p>I was looking through some of my photos from the past year and I found a couple where I really mananged to throw the background out of focus with my A720. Of course, I was just inches away from my main subject, so pretty much any camera with a macro lens could have done the same thing.<br>

<a href="http://bstinshoff.aminus3.com/image/2010-04-11.html">http://bstinshoff.aminus3.com/image/2010-04-11.html</a></p>

[dave_redmann]

<p><em>I've been hoping one of the more adventurous manufacters . . . might approach this through firmware . . . an algorithm that could simulate the DOF of different focal lengths and apertures based on the distance the camera calculates the focus point to be at. Perhaps this is hugely more complicated than the other existing firmware lens corrections.</em></p>

<p>Yeah, I think you are gross underestimating the complexity of the task. <strong>To really do it right</strong>, the camera would have to know the distance to the point that every pixel depicts. To get that, I can't see any method other than the lens running through its entire focus range, evaluating each pixel at each step of the way to see where it is most sharp (and thereby determine its distance), and then apply a post-exposure blurring process proportional to the distance between the pixel and the plane of focus (which would theoretically be easy enough if it had the distance-to-pixel data and a lot of processing power). But this would probably mean a <em>very</em> slow pre-exposure analysis, and would require both the camera and the subject to be totally still. And of course, insofar as the effective focal length of most (all?) lenses changes slightly through their focus ranges, the camera would have to adjust for the fact that something depicted by one pixel in the senor will be depicted by a different pixel on the sensor at a different focus distance. If you are going to really give the camera that much time and steadiness, and require a still subject, you almost might as well just use a bigger camera.</p>

<p>Now that's not to say that <em>nothing</em> could be done. Maybe one of the simpler techniques would be some sort of pixel-level blurriness analysis, and where the blurriness exceeds some threshold (or where it's notably more than it is at the least blurry point), the camera would add proportionally greater blur. That would tend to simulate less depth of field, but of course it would also exaggerate motion and maybe cause other artifacts.</p>

 

[bill_tuthill]

Fuji P&S models have so-called Pro Focus mode, which throws the background out of focus. It did not work well at first (F70EXR) but seems fairly reliable on the F550EXR. Here is the marketing image.

 

http://g-ecx.images-amazon.com/images/G/02/uk-electronics/product_content/fuji/f80_pro_focus.jpg

[ilkka]

<p>You need a camera with a bigger sensor. Enclosed picture is with Ricoh GXR and 33mm macro lens at F/4. The camera is small, but it uses APS sized sensor, similar to most DSLRs. I needed to stop down a bit to get more depth of field. The maximum aperture of that lens is 2.5. Similar pictures can be made with Olympus/Panasonic mcro 4/3 cameras and Sony NEX cameras. Sigma does not focus close enough, but DP-2 with close up lens might be able to do it. </p><div></div>

[bill_tuthill]

Here is the F550EXR at its long end, 360mm crop equivalent. In macro mode you can get quite close, in this case about 1.5 meter. I think bokeh is a little better here than with the GXR 33mm macro. Very good texture on the rock rose, but the red and blue fringes, left and right, are puzzling: not all images in the batch showed this.<div></div>