Why Digital is Dying?

[Biggsy]

Thanks for that, Damon.  It's great that the article actually answers the question!  (Sorry I didn't read it all to find it for myself).

Interesting that 15 MP is about the limit for APS-C with a bog standard lens*, and the lens I mentioned would benefit from more pixels as it peaks before F8.

* This equates roughly to a Pentax K20D with the kit lens.  So that's an excuse to upgrade from my K10D, and also not to bother with film in the hope of much higher resolution, unless using the best lenses.

[pcolbeck]

This thread is great. It's given me enough bedside reading to keep me going for the next few weeks. Thanks guys.

[frankly frankie]

It looks to me like the 4:3 format has a lot of merit in it.

That won't win you many friends!
I think in the long term you're right but at present people seem to get hung up on the downsides of a small(ish) sensor without noticing the upsides.
In practice, so far all that has been achieved is to push Olympus and Panasonic into producing some designed-for-4/3 lenses which are very high quality - which is relatively easy to do because of the small sensor, but OTOH they need to be good because of the higher image magnification (in the end product, eg a print). 

Which wins out - the ease with which very good lenses can be produced for a smaller image target, or the necessity for such lenses to be more than just 'very good' - I don't know.

[pcolbeck]

Makes for a rinky dink DSLR though. I have an Olympus E500 and its tiny compared to some others.

[tonycollinet]

The main problem (for me) with smaller sensors is the correspondingly wider depth of field. It becomes difficult/impossible to isolate the subject using dof.

[Really Ancien]

The main problem (for me) with smaller sensors is the correspondingly wider depth of field. It becomes difficult/impossible to isolate the subject using dof.

That's a compelling reason for larger sensors, but the discussion we have had shows that the low f numbers reduce resolution due to abberations, so you don't actually need an enormous number of megapixels when working with shallow DOF. The message I have got from this debate is that the sensor array need only match the defintion of the lens at f8, above and below that the resolution is lens limited. If you are shooting a detailed subject such as a still life or a painting you should aim to do it at f8 on a tripod and lock the mirror, which is one argument against SLRs. Shallow DOF is often used in portrait work where some softening is desireable.

Damon.

[Biggsy]

F8 is OK as a rule of thumb, but the optimum aperture for resolution depends on the particular lens.   If bothered about this sort of thing then you need to look up MTF data for your lens.

Good SLRs have a mirror lock-up feature, which may be manually activated or built into the timer function in the form of a delay after the mirror goes up before the shutter fires.