I was looking at this comparison when I realised the camera on the left had a 2.0 crop in a mirrorless body made in 2012 while the camera on the right was full frame, had a mirror and was made in 1972. Notice the size difference there.

Now if you want to compare that same camera to a modern Digital camera with a full frame sensor and a mirror, you're looking at something like this. Notice that size difference.

I can't quite understand why that is. The main arguments I've seen for this is (1) electronics and (2) ergonomics.

  1. I don't buy this argument. Surely we don't need that much space to fit the electronics in this day and age where a dual core CPU, dual core GPU computer logic board is about the size of your thumb.

  2. I don't buy this argument either. Just look at the rise in popularity of mirrorless systems these days. This is not because people prefer EVFs to TTL OVFs (most would still like a good OVF given the chance), it's because these mirrorless systems are much smaller. Clearly the demand for smaller is there, no matter how much people say that bigger cameras are more ergonomic.

So in 40 years of technological progress, we've managed to match the size of a camera from the 70's only after ripping out the pentaprism and putting in a much smaller focal plane. Seems silly, no?

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    \$\begingroup\$ I don't know about other pros, but I spent good money on motor drives not because I needed auto film advance, but so that the camera handled better. I can't think of a single reason (other than street stealth) why any working photographer would want one of the new compacts. \$\endgroup\$
    – user2719
    Commented Jul 7, 2012 at 9:04
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    \$\begingroup\$ I too am baffled about how huge consumer DSLRs are. My Nikon F/Ftn from 1970 was considered a full featured professional camera, yet my Canon D50 is much larger. I understand that modern cameras have tons of features, but Moore's law is still the law of the world. Could this just be a case of bragging rights? Mine is bigger! \$\endgroup\$ Commented Jul 7, 2012 at 19:11
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    \$\begingroup\$ Size is a critical factor in ergonomics. Larger cameras are easier to hold, offer more room for better button and dial placement, have larger areas of rubbery grip, offer additional informational screens for quick examinations of settings, etc. etc. The more we shrink camera bodies, the more ergonomics will suffer. For some people and some shooting styles, that won't be a problem, but compact cameras don't hold a stick to the ergonomics and rapid functional use of a large DSLR. And they never will (...unless we somehow manage to commercialize mind-control...in which case, all bets are off!) \$\endgroup\$
    – jrista
    Commented Jul 9, 2012 at 3:45
  • \$\begingroup\$ Unfortunately, as seen in the answers below, it's sheer amount of technology found in modern (D)SLRs that makes them so large. The Nikon F6 which is still being sold today is as big as a DSLR because it's fully featured. I guess the question could then move onto, "Why is it so imperative that every DSLR be an autofocusing, feature packed behemoth and why can't we have a manual but digital SLR the size of an FM2?" The only way to shoot a full frame image in a small SLR now is to shoot film :-( \$\endgroup\$ Commented Nov 28, 2016 at 4:17

3 Answers 3


DSLRs have expanded massively is terms of features since the 70s, now your entry level DSLR has comparable AF system, speed, shutter as a pro SLR from the 90s!

The D800 pictured has to incorporate many things absent from your 70s SLR

  • tough weather sealed metal chassis
  • pop up flash
  • AF sensor below the reflex mirror (why the camera is taller)
  • large battery
  • sensor, CPU, image processor, IO boards, metering sensor, LCD screen, top LCD screen
  • two memory card slots, including compact flash, which is itself huge
  • multiple external connectors
  • ribbon cables to connect the above
  • high performance mirror mechanism and metal bladed shutter capable of 1/8000s instead of simple cloth shutter

If you compare the D800 with a full featured film SLR such as the Canon 1V there isn't much difference.

There is demand for cameras of all sizes and so there are products to match. The reason micro 43rds cameras have a smaller sensor is as much to do with economics and lens size as it is to do with camera size. These days people aren't content with pancake primes, they want wide angle lenses and zooms, the pictured OM with a 20mm lens, or a 28-70 zoom would be much larger.

It is possible to put full frame sensors into smaller bodies, look at the Leica M9:


The reason no-one has done a full frame digital version of the OM-1 is that it would be leica prices, digital sensors don't scale as well as film!

  • \$\begingroup\$ Also look at the controls: On the front alone, the D has twice as many controls as the OM, and those require room. Someone shooting the D can flick the focus mode switch from single to continuous by feel and get the shot while the OM shooter has pulled the body away from his face and is making his way through menus. \$\endgroup\$
    – Blrfl
    Commented Jul 7, 2012 at 13:25
  • \$\begingroup\$ I think your last sentence nailed it on the head Matt, it's all about the price :) But ignoring sensor size for the moment, comparing top end DSLRs to top end SLRs like the V1 and F6 below would be missing my point, ie. sure we can go big on the high end but why can't we go small on the lower end? If we could fit a pentaprism in a tiny camera in the 70's why can't we do that in a crop camera today? The bottom of the range DSLRs are still way bigger than the OM-1. Conversely the OM-D has pretty much all those features except the mirror, and instantly it's way, way smaller. \$\endgroup\$
    – kLy
    Commented Jul 8, 2012 at 0:27
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    \$\begingroup\$ @kLy: SLRs offload all of the image processing onto the lab where the film is developed, so they can contain almost nothing beyond what's needed to handle and expose the film. DSLRs have to produce a usable image in-camera, and that hardware has to go somewhere. I if you were to spec out a full-frame camera that could only produce raw files, had no post-shot preview and the same primitive metering and controls we had in the 1970s, it would be the size of an OM-1. It also wouldn't sell. \$\endgroup\$
    – Blrfl
    Commented Jul 8, 2012 at 13:34

A full-frame DSLR like the D800 needn't be much bigger than a top end film SLR.

And the F6 is a lot smaller than the F5 which weighed 1,445 g including batteries. The D4 weighs 1,340 g

DigitalD4 FilmF5


Interesting thread - however outdated.

Nikon released the DF Full Frame DSLR with a refined body that is close to the classic SLR form factor. That was a few years ago already so I suspect we'll see another evolution soon.

Unfortunately, if you want something smaller you still have to go mirrorless. Mirrorless camera technology has advanced quickly and cameras are now engineered smaller than ever. Sony's RX1 is much smaller than most SLRs from the 70s. The more recent A7 series is also tiny while keeping a pretty good grip and button/dial configuration.

It is no longer true that FF DSLRs have to be huge, blocky dinosaurs. We could easily see cameras like the Nikon DF refined into a smaller form factor - or mirrorless technology could advance to the point where we no longer miss the mirror.

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    \$\begingroup\$ Actually, it's not that close. The DF is quite a big thicker than an F3. \$\endgroup\$
    – inkista
    Commented Jun 16, 2015 at 20:48
  • \$\begingroup\$ I'd like to include the Sony a7 as well. It is a full frame camera and is very small \$\endgroup\$
    – Janardan S
    Commented Jul 13, 2016 at 10:56
  • \$\begingroup\$ Adding to this, the Leica M10 and Sony A7 cameras are prime examples of how miniaturised the digital components have become now in 2017, to the point where I can't imagine how a Nikon "DF2" couldn't become a compact full-frame DSLR. Perhaps it's because I'm so used to manually focusing and enjoying simple matrix metering on my 80's Nikon FA that I wish such a digital camera existed. It's disheartening that any full frame DSLR must be a noticeably large body. I want a digital reflex camera I'll enjoy carrying while abroad! \$\endgroup\$ Commented Apr 7, 2017 at 1:36

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