[VoiceOfReason]

I keep reading in here the people want mirrorless, and I've seen some of the mirrorless cameras. Other than being smaller, what is the real advantage of them? I've been reading the rumors thing about a new mirrorless with the same sensor as the K5, but from what I've seen so far I'd rather keep the K5 I have. I really am curious, what is the advantage of mirrorless, and why do so many seem to want it? I really don't know a whole lot about it, so can someone give me a list of advantages over a traditional DSLR? Actually, is there a lis showing the advantages of one over the other? Thanks for any responses.

[Anvh]

I think no body really wants them, it has mostly to do with an interview with someone from Pentax.
He said he would like to see or try something like a 135format or 645 camera in mirrorless form.

I can actually see how mirrorless can be beneficial for 645 at the moment, the format is mostly used for landscapes and studio photography.
But FF or APS-C i still would like the optical viewfinder for the faster moving subjects.

anyway.
Benefit is less mechanical components so a cheaper camera.
Also in lower light the brighter LCD screen is quite a blessing.
Downside is that the sensors is constantly on is that thing will heat up causing noise and it will eat batteries.
Also there is a tiny bit of lag what is seen on the LCD screen, since i shoot with both eyes open i do get sick when i use it for some time...

[liukaitc]

I think one benefit is video aspect..just look at panosonic mirroless camera..now becoming more video oriented than still for many people...

[ofer4]

Mirrorless also provides the potential for (much) faster fps shooting and less vibration from the mirror movement itself.

[Michael Shea]

Manufacturers who have developed mirrorless systems aren't particularly looking to attract existing DSLR users. The targets were and still are people who had/have become accustomed to the convenience of point & shoot and mobile phone cameras. When you think about it, that is a vast number of people. Pentax will hope that new customers buying into its mirrorless system will eventually purchase one of its higher-end cameras and use some of the lenses they've accumulated in the process. I've got four micro four thirds cameras but feel I've outgrown them. Nonetheless, there are many occasions when I'd rather have a Panasonic or Olympus camera with me than a K-5, superior camera though it undoubtedly is. There is a lot to be said for travelling light.

[Livanz]

Logically , by diverting some 15-30% of the light provided by the lens would the image on the sensor be exacly the same quality as with a an optical viewfinder ? The answer is NO , you loose some 15% in image quality , and this is not something that adds will tell you , they only talk about the advantages ... Secrets of the Sony A55
No problem as long as Pentax has the OVF K-5 in it's line-up , a parallel EVF with 15% loss of image quality at a low price could be a nice entry-level camera , nothing wrong with that as long as you know what you are buying .

[Anvh]

I think one benefit is video aspect..just look at panosonic mirroless camera..now becoming more video oriented than still for many people...

Doubt its because it hasn't a mirror, just look at the Canon 5 markII for instance and the Nikon D4.

Mirrorless also provides the potential for (much) faster fps shooting and less vibration from the mirror movement itself.

They could make it so off course that the mirror doesn't flip back, and you should be able to get the same FPS.

Logically , by diverting some 15-30% of the light provided by the lens would the image on the sensor be exacly the same quality as with a an optical viewfinder ? The answer is NO , you loose some 15% in image quality , and this is not something that adds will tell you , they only talk about the advantages ... Secrets of the Sony A55
No problem as long as Pentax has the OVF K-5 in it's line-up , a parallel EVF with 15% loss of image quality at a low price could be a nice entry-level camera , nothing wrong with that as long as you know what you are buying .

Sorry to break the news but those Sony cameras you mention aren't mirrorless

[RioRico]

Besides all the excellent points made already, there's also the much shorter possible register aka flange-focal distance (FFD). Sony can use the same size sensors on Alpha dSLRs with 44.5mm FFD, and the NEX mILCs with 18mm FFD. The shorter register can have native lenses that are small, and wide lenses that are simple (compared to longer-FFD glass), and that can yet accept longer-FFD lenses via adapters.

Does this lens flexibility offset the physical limitations of current-generation mILCs? Not yet for me.

[demp10]

If one uses mostly manual focus lenses especially in the telephoto range, it is very challenging to get perfect focus through the mirror and viewfinder even with split screens and micro prisms. Live view is the preferred way with up to 10x magnification, but in my K-7 drains the batteries very fast and makes it impractical for prolonged sessions without several extra batteries. If a mirrorless camera has improved battery life and additional focusing features, it will be a welcome addition to many.

I will not abandon my K-7 and K10D but I would definitely consider getting a mirrorless and attach it to 400 M permanently. And if it has the K-5 ISO performance, that will make an excellent combination for wild life. I was seriously considering getting an Olympus mirrorless with a K adapter, but now I'll have to wait for February.

[luftfluss]

Logically , by diverting some 15-30% of the light provided by the lens would the image on the sensor be exacly the same quality as with a an optical viewfinder ? The answer is NO , you loose some 15% in image quality , and this is not something that adds will tell you , they only talk about the advantages ... Secrets of the Sony A55
No problem as long as Pentax has the OVF K-5 in it's line-up , a parallel EVF with 15% loss of image quality at a low price could be a nice entry-level camera , nothing wrong with that as long as you know what you are buying .

You're thinking SLT, not mirrorless.

Another side-benefit of mirrorless is that the EVF is potentially better for manual focusing - the EVF can be larger than a typical APS-C OVF - and also the image can be magnified in the eyepiece.

Also, the Contrast Detect AF might wind up being more consistently accurate than the Phase Detect AF in DSLRs.

[hcarvalhoalves]

Pros:
- Smaller body
- Less mechanical parts, more sturdy cameras, less QA issues
- Possibly more energy-efficient
- Possibly faster shutter speeds
- Bigger, 100% viewfinders without negatively affecting body size or price
- EVF can preview DoF, exposure, manual focus assistance

Cons:
- EVF technology still more limited in terms of resolution and brightness than true-to-life OVF
- Some argue phase-detection auto-focus is still faster than contrast-detection

The EVF is either the biggest pro or con, depending on how you use it. I would be more happy with a big, 100% coverage EVF in a compact body than the sucky OVF in my K-x.

[Anvh]

Another side-benefit of mirrorless is that the EVF is potentially better for manual focusing - the EVF can be larger than a typical APS-C OVF - and also the image can be magnified in the eyepiece.

Also, the Contrast Detect AF might wind up being more consistently accurate than the Phase Detect AF in DSLRs.

You can magnify optical viewfinders as well, pentax make two at the moment. a 2x and 1,3x or something like that.

CDAF is more accurate but PDAF is faster and it knows which way to focus so it can track focus, something you can't do with CDAF.
Some brands now convert some pixels on the sensors to PDAF like focussing, nikon 1 use them for example.

[Anvh]

- Possibly more energy-efficient

How does that work?

The sensor, processor and a LCD screen needs to be on if you want to use an EVF camera...
With optical you only have the lightmeter, the little info bar and once in the while the AF system.
So how can EVF be more energy efficient?

[JinDesu]

Mirrorless CON: Longer sensor use will result in warmer sensor.

[hcarvalhoalves]

How does that work?

The sensor, processor and a LCD screen needs to be on if you want to use an EVF camera...
With optical you only have the lightmeter, the little info bar and once in the while the AF system.
So how can EVF be more energy efficient?

I say possibly, but very likely, since there's more room for future improvement on OLED and sensor technology than in DC motors to drive the mechanics. Solid-state technology continues to evolve, nowadays we have transitors with a fraction of the resistivity we had 10 years ago, and the electronics industry will keep pushing this further with smarter materials (e.g., graphene).