megapixels or sensor size

[PeterW]

Been having a long conversation today with my photog friend Danny, the one who gave me the scanner. It was a bit one-sided because Danny did most of the talking, I did the listening.

He still does some film work, mainly 5x4, but for small stuff, 35mm, he's gone entirely over to digital, because that's what his clients want.

We got on to numbers of megapixels, and Danny maintains that megapixels by themselves don't mean a lot unless you know the size of the sensor.

Some of today's "cheap" compacts that boast 10 or 12 magapixels in big letters on the box together with image stabilization, five times digital zoom (note: digital not optical), red-eye reduction and whatever have, he maintains, tiny little sensors about the same area as the cross-section of a pencil. Modern electronics have made this a way of keeping the price down.

I got to thinking about this, something I seem to have a lot of time to do these days, and got to wondering if that's why I still quite often use my old 2.1 megapixel Epson 850Z. For quality it knocks the socks off most of the £80 - £90 compact digitals (with no viewfinder) in the catalogue shops at the moment.

Here's a picture from it taken a couple of years ago


The restored Ticked Trout at Wye in Kent.

PeterW

[Doug T.]

Peter,
I don't know for sure if your friend is right or not, but it does make sense.
I think I read somewhere that digital SLRs have sensors of the same size as a 35mm frame. Again, I'm not sure.
It's something that's worth looking into.
I use my Fuji FinePix S5200 all the time. It has 5.1 megapixels, and I get great shots with it.
It has an optical viewfinder as well as a screen. I use the optical finder most of the time, but when using a tripod, I use the screen. It's a great camera, and wasn't all that expensive either.

Doug

[SidW]

I agree with the your friend, Peter. That's why they have a noise (grain) problem. Doug, most DSLRs have a sensor that's
smaller than full 35mm frame, the sensor area of Canon EOS models is roughly 2/3 of full frame. A few flagship models have
full 35mm frame size sensors.

The Tickled Trout. Peter, the number of lunches we've enjoyed there. Several generations back, the family were near Wye,
at Molash (or Moldash as it was then), and found their wives-to-be at places like Boughton Aluph or Challock. You and
I are perhaps the only ones here who know that's pronounced Chollock.

[nikkortorokkor]

if I ever become a publican, I'll use that Tickled Trout name!

Peter, your friend's advice chimes with my understanding of the matter.

Our daughter, an industrial design major, is planning to buy a "serious" DSLR and is looking at an EOS 7D. Thus, I now know a little about 'better' sensors.

The"single digit" EOS cameras use a "full-frame" sensor - so it is the same size as a 35mm neg. Well, all do except the 7D, which uses an APS-C CMOS sensor. 'APS-C' stands for - you guessed it- advanced photo system classic. So the sensor is the equivalent of the quickly-defunct APS negative.

These digital sensors were obviously cribbed from existing film sizes, whilst the Olympus/Kodak 4/3 sensor was the first 'new size' to be designed from the ground up with DSLRs in mind.

Here, care of Wikipedia, are the relative sensor sizes:



As for megapixels, Ken Rockwell has a good iconoclastic essay here which explains why your old,'low megapixel' camera performs so well:

www.kenrockwell.com/tech/mpmyth.htm

I find this quite useful.

MT

[mickeyobe]

Michael,

Thank you for this and for that excellent article by Ken Rockwell.

Mickey

[daveh]

Megapixels v sensor size? It's never quite as simple as that. Lens quality and file compression have to be taken into account: also is the 'engine' that saves the picture makes a difference. That final quality also depends on the photographer is a given.

I would disagree with Mr. Rockwell that 640x480 pixels are enough for a good 6x4 print. Yes, it can be fine if the shot is not exacting, but get some diagonal lines and stepping becomes obvious. I think in his determination to prove his point he has gone over the top with his argument. Also 640x480 only works if you are printing full size from the file. By the time it has been straightened and cropped it has totally 'gone'.

The 'engine' determines how fast, after the shutter is pressed, the photo is actually taken. I have had some cracking photos on the Panasonic FZ1 and FZ20. Good clean photos at 2mp and 5mp respectively. However try either for action photos and they struggle. The Canon 7D is the nearest thing to an instantaneous photograph I have in a digital camera, but I'm not sure even it is as fast as an equivalent film camera.

[nikonbob]

PeterW

I think your friend is correct in that, with present technology, the size of the sensor does matter as far as when noise becomes a problem. For me digital noise in a photo is similar to grain in film and I don't care for too much of either. The larger the film format the smoother the look of the image and so it is with digital. Small sensors with the same mp count as larger sensors become noisier quicker. I have two small sensor-ed non DSLR cameras, one with 6mp and one with 10mp, and the 10 mp one is so bad for noise I will not use it above it's native ISO but it will do enlargements better that the 6mp one. Both are more than good enough for web used. The D700 blows both out of the water as far as usability at high ISO goes and a few other things too. The fastest film that I used to use was 800 ISO C41 and the D700 is usable far above that. As far as I can see most digicams available today have specs far above what is needed to display on the net. OTH if you want to do enlargements, especially if you crop, more mps are better for any given size sensor. So far it is a trade off between mp count and how soon noise becomes a problem or wanting the ability to crop/enlarge for any given size sensor. Still no free lunches.

Bob

[Deleted]

I guarantee you my Nikon D50 with a 6.5 mpx sensor will produce a sharper and larger photograph than any point an shoot with a 12 mpx sensor. And it will produce better results in lower light, too.

[daveh]

My Canon 7D, at 18 megapixels, is better in all respects than my Canon 30D at 8 megapixels: they have the same size sensor.

[keith201]

One of the best sites I have come across is www.cambridgeincolour.com It has a gallery of lowlight photography that blew me away and the tutorials are the best I've seen.

[Berndt]

I think, modern digital cameras do have enough pixel ... but the sensor size is still too small. I still miss the chance for getting a "decent depth of field" in wideangle shots. There are still just a few super expensive Full Frame cameras available and that is just what people had on ( 35 mm ) film for decades.

[andys93integra]

Not to mention the new Nikon D800 with 36.3 megapixels, which is in fact not overkill for a FF sensor. The pixels are actually larger than the D7000 at 16.2MP and a crop sensor. My uncle is getting his D800 next week, hopefully, and maybe I can grab some files from it and share them.

Andy

[daveh]

It's horses for courses.

small(est) sensor size:
pro:
better depth of field.
smaller lenses as they require less coverage.
25:1 (and more) zoom lenses possible in a smaller size and/or weight than an old 35mm SLR standard lens.
cons:
too much depth of field.
wide angle is less wide angle.


With 35mm, and larger, sensors, the difference between old and new is largely lost.

For me it's a case of adopt, adapt and adjust. Or as the song goes in the King and I "Getting to know you, getting to know all about you..."