PIX 2015

My dream full-frame camera.

Started Apr 3, 2014 | Discussions thread
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Re: Dreaming is free, large sensors cost money
In reply to Erik Magnuson, Apr 6, 2014

Erik Magnuson wrote:


I think there is a vacuum in the realm of what products are available .

It's so hard on the internet to tell if someone is joking or clueless.

It seems a little obvious that many of us would like to have a very durable and hi quality digital back for a small view camera . In particular a 6 cm by 9 cm view camera .

It's so obvious that the first one was made back in 1991. Try googling names like Leaf, PhaseOne, Imacon, and even Better Light for something a little different.

The really good sensor for a 6 X 9 should be available for less than the cost of a new digital Full frame .

See, it's statements like this that make it hard to distinguish between satire and ignorance. But we'll get our affordable 6x9 shortly after we get our flying cars for less than the cost of a new luxury car.

(Hint: if you not joking, the largest sensor back you can currently buy commercially is only 53.7x40.4mm. The smaller 44x33mm CMOS sensor version starts at $35k. See http://www.dpreview.com/news/2014/01/24/phase-one-announces-iq250-50mp-cmos-medium-format-back )

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The never ending 'equivalence' debates provide an interesting insight into this. The thing with digital is that enlargement is a free lunch. That wan't true with film, where enlargement had to be done with a separate optical system, and in general, the less enlargement the better the end quality - hence the use of larger formats. However, with digital all that matters is how many pixels you have, how much light they can collect and what are the DoF and diffraction function as scaled to sensor size.

So, for instance you could do everything that you can with a 24MP FF camera with f/1.4 lens and 100 ISO with a 24MP mFT camera using a f/0.7 lens and 25 ISO - so long as the lenses had the requisite resolution with respect to sensor format. Taking it the other way, the crop factor between 35mm and 6x9 is about 2.3. So, if you're working with a 36MP FF camera at f/1.4 and 100 ISO, it's producing much the same results as would this hypothetical 36MP 6x9 camera at f/3.2, 500 ISO. Most 6x9 cameras didn't have lenses as fast as f/3.2 - so the only advantage to the 6x9 is that absolute noise advantage it could get working down to 100 ISO (equivalent to 20 ISO on the 35MM). If your FF camera had a 20ISO capable sensor, it could match the 6x9 for everything.

It appears for a long time that f/1.4 FF equivalent is the standard for 'fast glass'. Given that if you go much smaller and you're beginning to hit against the f/0.5 limit and there is limited advantage to going bigger and it has huge cost implications, FF really is a sweet spot with that respect. Of course, if you factor portability and cost, smaller formats have a great deal going for them too.

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