Mirrorless with the Highest IQ ?
Thanks, I must add "It has to be interchangeable Lens"
Leica M9 - Range Finder - don't have mirror and have interchangeable lens.
However, you may not be able to afford it.
You can get high IQ if you have good lens.
With the right adapter, you can mount different type of lens on the mirrorless.
The Sony NEX with the right lens may be what you are looking for, because it have larger sensor than m4/3 mirrorless.
Looking past the very high end Leica M9 and M lenses, and their very high price... technically speaking, the Leica M is mirrorless, but that's like saying... technically speaking, Angelina Jolie is attractive. Accurate, but it doesn't convey the level of excellence or the fact that they're out of reach of most of us.
Theoretically, the Sony NEX7 or Fuji XPro1/XE1 bodies have the potential to deliver the highest possible IQ, with a slight nod to the Fuji sensor.
But, NEX doesn't have much native high grade glass right now, and Fuji's AF is a bit slow and glass selection is a bit limited, though all of the Fuji glass is very sharp.
Realistically, the Oly EM5 has a greater selection of high grade lenses, plus the same (albeit slightly smaller) sensor as the NEX7, plus the most effective image stabilization system available today.
True that one can use the larger Sony Alpha glass on the NEX and get improved IQ, but one can also use the ultra sharp Olympus ZD lenses on the EM5 and get stunning IQ. There are tradeoffs for both approaches: NEX uses a pellicle mirror setup to AF the Alpha glass which costs you between one half to one stop of light to the AF system, while the very high grade ZD lenses have sluggish AF on the EM5, in the 1-2 second range (though that will be fixed in the upcoming OMD-Pro).
In both cases, the mirrorless setup is no longer small, because the lenses are large.
So it all becomes a question of what you want - the best IQ, the smallest size, the greatest convenience? DSLR style shooting or rangefinder style? And what glass do you already own?
I use an EM5 with both ultra small and very sharp fast MZD prime lenses and larger but fast and ultra sharp ZD zoom lenses. It becomes a dual purpose system: very small and portable with fast primes when you want it, or larger and very capable with fast zooms when you want it.
my bad Lecia M had interchangeable lens. but still it is way out of budget.
Sony Nex-7 seems much better option. Which 2 lens should be used ?
I am not a Nex user.
You should post your question in Sony Nex talk.
They should be able to help you find the ideal setup
Try a Pentax K-01, they can be had cheap right now as they are being discontinued prior to the newer body being introduced, and there are a TON of lenses that will give you great IQ, as it takes ANY k mount lens! I have been tempted to supplant my back up body with one and a DA 21 lens.
Oh and it is APS-C sized sensor as well = Good of IQ as a DSLR.
“For every problem there is a solution which is simple, clean and wrong.” Henry Louis Mencken
I have an NEX7 with a Tamron 18-200, I don't think you will find a smarter outfit then this, 24mg 10FPS, great panaramas, the wonderful focus asist, I sold $ 12.000 worth of heavy 5D SLR stuff and could not be more pleased with this move, That after 55 years using Canon and Nikon: Larry
Best image quality is likely from Fujifilm X-Pro 1, X-E1 or a Sony NEX-7 given their large sensors. Both are limited today in terms of available native lenses. The Olympus OM-D M-E5 and the Panasonic DMC-GH3 are the two best micro 4/3 format. They are perhaps a "notch" down in IQ due to their smaller sensor format (many will argue no) but they offer other advantages.
Look at these 4 models and see which has the best combination of attributes for your needs. You should look beyond just image quality at, lens quality and variety, size and weight, ergonomics, controls and menuing, raw support etc. Lastly, consider the size and weight of the entire system and not just the body.
Does any custom firmware exist for Nex 7 ?
The difference in IQ between APS and 4/3 sensors is now very small. The nod would still go to APS in certain instances, but not all.
The biggest factor today in IQ would be the lens(es) you use. Both NEX and micro43 can take virtually any lens ever made, if not relying 100% on native mount lenses.
Also, if you do consider the NEX-7, be aware than a replacement is expected before summer.
Which MirrorLess camera has the highest IQ or it is considered as so ?
At low ISO and in decent light the Sigma DP Merrill cameras reign supreme right now for IQ..
There are no interchangeable lenses, but the price for the camera "and" a superb lens is less than the price for an equivalent lens alone for interchangeable lens systems.