Comment by bad_user | Hacker News Reader

Comment by bad_user | Hacker News Reader

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     You can just produce a composite image that's sharp 
     all over… – but what fun is that?

With DSLRs that have huge lenses with large aperture sizes, the depth of field varies a lot and those lenses also have a sweetspot in focal-length / aperture for which images produced are the sharpest. Lowering the aperture size increases the depth of field, but then you've got another problem as the shutter speed also has to be adjusted and you end up using a tripod.

Getting a picture that has everything in focus and is tack sharp can be seriously challenging.

To tell you the truth, while these photos with adjustable focus seem cool, focus is not my pain - what I want is to be able to take great photos (the kind that 35mm cameras can do) for reasonable prices, preferably with something that fits in my pocket.

And to expand on the point above - focus is not painful when the camera has enough focus points. I played with a Nikon D3s that has a whooping 51 auto-focus points; let me tell that it's freaking awesome, as it can track your subject as it moves. The problem is that consumer-level DX DSLRs only have like 11 focus points, which is still cool, but point&shoots suck badly in this area, most of them focusing only in the center of the image.

Another problem with this project that I can see - people don't like playing with their images on the computer. When you take 500 photos in a single day, and another 600 photos the next day (like when going on a trip), it's really painful to carefully adjust each image, not to mention that the RAW formats are huge and seriously cuts in the number of photos you can take ... yeah, making adjustments is great, but I prefer making more photos, that's why I shoot in JPG and don't regret it.

Focusing with point and shoots should not be a problem. They all have a huge depth of field due to their small sensors, so you have to try really hard to put something out of focus. Smudged pictures on point and shoots are usually not a result of lack of focus, but something else (e.g. shaky camera).

Even with DSLRs you usually only need one focus point. You can focus at the center and re-frame. It is very simple to do, and is much simpler than choosing a focus point (and much safer than trusting the camera to automatically choose a focus point for you). Multiple focus points can be very useful in certain rare circumstances: when shooting something really fast off of center without being able to pre-focus or when your camera is bolted down on a stand. Even then I cannot possibly imagine one anyone would need 51 points. This is obvious feature creep.

But yeah, I am really not sure who the intended market for this camera is. Focusing is just not a pain point, in my opinion. This camera could be used by artists and professional photographers to play around with the depth of field to get a great artistic shot, without making their subjects wait. But with the micro-lens design, will it have enough image quality for professionals? I guess we will see.

You cannot re-frame when shooting moving subjects - kids playing, sports, birds, cars, motorcycles, boats - there's all kinds of instances in which your subject doesn't stand still and even has unpredictable moving patterns, so keeping your subject in the center of the frame and/or re-framing is in many instances not feasible.

Nikon DSLRs have this 3D tracking feature in which you select an object to keep in focus and it refocuses based on its movement inside the frame when it hits the focus points. And when the subject exists the frame and re-enters, auto-focus comes back. 51 focus points may seem like feature creep, but as I said, it's freaking awesome when shooting moving targets like birds.

Even for subjects that are still, like for portraits, you have a lot more freedom for composition as you just select the person's eyes and then you can move around while the eyes are kept in focus.

Of course, you can do a good job with a single focus point, but professionals and amateurs need predictable results, because good moments for taking photos are rare and you don't want to screw up because your camera wasn't properly focused.

That's why I can see partly the utility of this technology here, but on the other hand I can see serious problems with it too, the biggest one being that for most people quantity of photos trumps quality. Another problem that I can see is the one I mentioned above; precise and predictable focus is not that much of a problem with modern cameras. And yet another: mega-pixels and quality of optics count a lot. Well, maybe once passed a certain threshold, the there's less ROI from a higher MP, but still, under 6 MP a camera is only usable for publishing on Facebook.

My consumer DLSR has 4 FPS and I don't worry about focus as I just continuously shoot like 20-30 pictures in a row to make sure one of them is good, and usually one of them is.

> under 6MP a camera is only usable for publishing on Facebook.

2560x1600 pixels is 4.1MP. At 1:1 that will completely fill the most monstrous computer monitors one can get for under about $10k. At 300 pixels per linear inch (a very reasonable resolution for photos; about the same as the iPhone 4 "retina" display) it will give you a picture with 10" diagonal.

Unless you're making posters or big prints for photographic competitions or something, even at 4MP raw pixel count is not going to be your problem. It's completely untrue that below 6MP your pictures will be useless for anything beyond Facebook.

(Of course pixel count starts to matter more if, e.g., you're taking pictures of distant birds or distant celebrities with a not-especially-long lens and you need to crop heavily. Most photographers, most of the time, are not doing that.)

Don't forget about pixel quality (it's understandable because the industry has been encouraging it for years).

A 6MP sensor would produce a fantastic 10"-diagonal print if its pixels weren't affected by noise and it was combined with a high quality lens. Unfortunately sensors of that resolution are typically small (=noisy pixels) and placed in point-and-shoot cameras (=cramped, low-quality optics).

Or you could buy a top of the range pro DSLR from 5years ago with this resolution, with fantastic lenses and bullet proof build for the price of a modern entry level camera

I find the higher mega-pixel really helps on cropping. Especially when photographic wildlife like a dragonfly its nice to be able to crop a photo to just focus on that while still maintaining resolution. For me 10MP minimum is for this purpose rather than large prints. 2c this looks like a really cool technology, I would love to see it built into phones.

Focusing with the center AF sensor only and recomposing will generally put the plane of focus behind the intended subject (assuming the lens does not have an extraordinary degree of field curvature). The geometry is easy to see if you remember that your focus distance is the distance from the sensor/film plane to the subject, not the distance from the lens to the subject. The problem is more noticeable with a wider lens, a larger aperture setting and a closer subject, but it's always there. That's why Hasselblad (who only offer one AF point in the H4D camera system) has incorporated positional sensors and focus correction in their latest models.

If your camera offers the option, choose a focusing composition that will put your subject as close as possible to its final position in the picture and use the focus point closest to that position.

"people don't like playing with their images on the computer."

...until they have a great shot ruined by improper focus. Or worse, an entire afternoon of great shots at a memorable event ruined by the autofocus switch set to "off". Us geeks may notice in time, but most consumers/users won't.

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