I want to give mirrorless a shot (I have always and only used DSLRs), especially because I'm enthusiastic for street photography and I want something agile when traveling. I'm also a time-lapse fan.

I see that Sony a7s is full-frame (never had one, would like to try!), but I see also many people (e.g., here) complain that big lenses make it big as a DSLR.

I found also the Fujifilm X-T3 very interesting, it looks more compact when using lenses (is it?) and well-reviewed, but it's not full frame and doesn't seem so good for timelapses (or is it?).

Many recommended me also the Fujifilm X100, but the fixed length makes it a little bit too much constrained in my opinion (even if it looks perfect for street photography).

What do you think about this? Are any valid alternatives for what I am looking for?

  • 5
    \$\begingroup\$ It depends what you mean by compact, and it depends what lens you want/use. All of the Sony Alpha 7 and 9 series cameras are full-frame, and they look pretty compact to me. There are compact lens options. If you look at a retailer like B&H or something, they have a pretty comprehensive listing and quite a usable website for whittling down options. \$\endgroup\$
    – osullic
    Oct 26, 2018 at 11:02
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    \$\begingroup\$ Also very relevant: When do the differences between APS-C and full frame sensors matter, and why? \$\endgroup\$
    – osullic
    Oct 26, 2018 at 11:06
  • 3
    \$\begingroup\$ @user6321 "Good" for low light condition does not necessarily always translate to "good" for astrophotography. Sophisticated noise reduction routines that help reduce image noise in many low light scenes can also "eat stars" when doing astro. \$\endgroup\$
    – Michael C
    Oct 26, 2018 at 12:50
  • 2
    \$\begingroup\$ Are you guys seriously contemplating getting a $2000 camera and pairing it with a lens which is primarily designed to be cheap? That's like getting a Mercedes-Benz and opting for a lawnmower engine. \$\endgroup\$
    – mattdm
    Oct 26, 2018 at 13:15
  • 1
    \$\begingroup\$ @mattdm They say, lawn Mowers are quite fast: youtube.com/watch?v=Xe5ldu2jB2E :D \$\endgroup\$ Oct 26, 2018 at 13:33

6 Answers 6


I don't think you'll find what you're looking for, because: bigger things are bigger than small things. Full-frame cameras are bigger than APS-C cameras Medium format cameras are bigger than full-frame cameras. APS-C cameras are bigger than 1/2.3" format cameras. Just like full-sized pickup trucks are bigger than commuter cars.

I think it likely that you've been somewhat seduced by the forum-discussion-driven mystique around full frame. There's not actually anything inherently superior about that particular sensor size. Yes, it's true that twice the light gathering surface area is nothing to sneeze at. But, exposure in photography works in exponents: doubling is just one stop. (Compare going from f/2.8 to f/2 or from f/2 to f/1.4.)

If size (and price!) are major concerns, APS-C is a pretty awesome sweet spot right now, and will be for the forseeable future.

You say:

Many recommended me also the Fujifilm X100, but the fixed length makes it a little bit too much constrained in my opinion

Which is valid; having an interchangeable lens system lets you pick the lenses that best fit your usage. I'd suggest looking instead at the X-T20, which is quite compact especially when paired with the 35mm f/2 lens or another lens from that series. There are equivalent options from Sony — and even though the Micro Four Thirds sensor is a bit smaller still, Olympus and Panasonic.

You could also look at the X-T3 (which, by the way, is great for time lapses; I don't know where you got the idea that it wouldn't be). However, it is significantly bigger and heavier; you will definitely notice the difference in carrying it all day. It's a commitment while traveling; while it's smaller than some alternatives, I wouldn't really class it as an agile travel camera. For that, go with the smaller (and cheaper!) line.

All of these can produce top-quality astonishing first-class images. You do not need full frame for that. Full frame is not a magic bullet that makes cameras better. It makes them different, and it inherently makes them different in a way which conflicts with your needs.

  • \$\begingroup\$ +1 so far the best answer/comment, I really appreciate it. My enthusiasm for a7s for astrophotography is because it's ff (wider, brighter) and has incredible performance even with high ISO. Check out this video. Up to know, I didn't find any comparable source for the x-t3...but if you do, please share it! :) But it looks also great for street photography (dive deeper here) \$\endgroup\$
    – user6321
    Oct 26, 2018 at 15:36
  • \$\begingroup\$ I find this a very good video on the subject \$\endgroup\$
    – user6321
    Oct 26, 2018 at 16:12
  • \$\begingroup\$ All modern cameras have incredible performance. Fujifilm even uses sensors actually produced by Sony. They are very, very, very similar from a technical standpoint. Don't be seduced by people nitpicking the details. \$\endgroup\$
    – mattdm
    Oct 26, 2018 at 16:20
  • \$\begingroup\$ I find all your argument interesting, and believe me that now the choice for me will be between the Sony a7s (not ii), Fujifilm X-T20 and Fujifilm X-T3. Btw, here's a comparison in size between them, maybe there is a better configuration for Fujifilms ? \$\endgroup\$
    – user6321
    Oct 26, 2018 at 17:09
  • \$\begingroup\$ Note that you have the X-T2 rather than X-T20 in that link. But even then, the difference in 2-dimensional image size really doesn't capture the difference in having one or the other around your neck all day. \$\endgroup\$
    – mattdm
    Oct 26, 2018 at 17:21

It would be helpful for you to rank order your priorities, including sensor size, camera size, and weight. Priorities cannot be equally important by the definition. Further, there is no single camera that meets every possible need. For instance, adding weather sealing necessarily increases weight.

Size and Weight

Although the sizes of the cameras you are considering are similar, their weights are quite different. (See these spec comparisons: 1, 2.) 

FujiFilm X-T2    507g
FujiFilm X-T20   383g

Sony A7S         489g
Sony A7S II      627g

Sony A7          474g
Sony A7 II       599g
Sony A7 III      650g

While it is possible for full-frame cameras to be made smaller and lighter, it is unlikely to happen any time soon because:

  • Sony has been increasing the weight of the A7 line with each generation, though the size has remained about the same.
  • FujiFilm has opted to stay out of full-frame.
  • New cameras from Canon and Nikon are even larger and heavier.

    Canon EOS R      660g
    Nikon Z6/Z7      675g

Lens Size

Lens size is a separate issue from camera and sensor size. Lenses with similar specs and designs will have similar sizes, regardless of sensor size or camera type.

  • FujiFilm's 100-400/4.5-5.6 APS-C lens (94.8mm x 210.5mm) is slightly larger than Tamron's 100-400/4.5-6.3 full-frame lens (86mm x 197mm).
  • There is currently no 24-70/2.8 lens in FujiFilm's lineup, but if there were, it would be about the same size as all the other 24-70/2.8 lenses.

Crop-sensor kit lenses tend to be smaller than full-frame kit lenses because they have different specs. When the aperture is kept about the same, the size of the lens will increase with the focal length. (It's pretty much because of the definition of aperture.)

  • MFT kit lenses are typically 14-42/3.5-5.6.
  • APS-C kit lenses tend to be 18-55/3.5-5.6.
  • Full-frame kit lenses tend to be 24-70/4 or 24-105/4.

Fast, constant-aperture zooms are large because they need to be. If you want to have smaller lenses, purchase smaller lenses, such as primes and variable-aperture zooms.

  • \$\begingroup\$ Thank you for your answer. I'm considering the Sony A7S (not II), which weights 486g. \$\endgroup\$
    – user6321
    Oct 27, 2018 at 6:35
  • \$\begingroup\$ If you mount it with the Samyang 35mm FE for the Sony A7 and Fujinon 35mm XF, you can see here j.mp/2SnSqiX that the Sony is the lightest one. \$\endgroup\$
    – user6321
    Oct 27, 2018 at 6:43
  • \$\begingroup\$ Btw, thank for the super useful analogies (e.g., size depends on focal length at equal apertures) \$\endgroup\$
    – user6321
    Oct 27, 2018 at 6:46
  • 1
    \$\begingroup\$ @user6321 According to the comparison site you link to, Sony A7S + Samyang 35/2.8 is heavier (489+108=597g) than FujiFilm X-T20 + XF35/2 (383+170=553g). The XF35/2 is also a better lens. Depending on how you rank the importance of image quality, sensor size, and weight, you may or may not go with Sony, and you may or may not need to swap out the Samyang lens for a heavier one. \$\endgroup\$
    – xiota
    Oct 27, 2018 at 7:25
  • 1
    \$\begingroup\$ Again, putting that Samyang lens on an a7 is fundamentally silly. Leaving aside technical image quality issues, it has a maximum aperture of f/2.8. The Fujifilm lens is f/2 — one stop faster. \$\endgroup\$
    – mattdm
    Oct 27, 2018 at 12:34

Keep in mind that any claims of compactness apply only to the camera body.

Due to focal length being... well... focal length, the body/lense combination has to be the same length. A 100mm focal length lense, for example, needs 100mm between the point of convergence and the sensor. If the camera body is, say, 2mm narrower because it is mirrorless, the lense has to compensate by getting 2mm longer. If it doesn't, it the lense doesn't work anymore.

This is also a good time to think about the ergonomics. I started photography in the film era, and camera bodies at that time were more compact - take a look at a Canon AE-1 for example. With a zoom or a telephoto on the front, they became unbalanced and there was a whole industry selling grips to make life easier. Camera bodies got bigger for a reason! They are easier to hold.

For these reasons, I am not convinced that a mirrorless body + a longer lense is going to give you the "something agile when traveling" you are looking for. For that, you need a smaller sensor which will give you a more compact body and more compact lenses.

  • \$\begingroup\$ Hm, have you check Canon DO lens, for example 400mm have length of 230mm. \$\endgroup\$ Oct 28, 2018 at 9:52
  • \$\begingroup\$ That is correct, but my point is for that lense to work on a camera body with a lense mount 2mm closer to the sensor, the lense would have to be made 232mm long instead. \$\endgroup\$ Oct 28, 2018 at 23:14
  • \$\begingroup\$ @RoaringFish - or have an adapter, like the Nikon Z7 and Z6 have. \$\endgroup\$
    – PKD
    Dec 11, 2018 at 21:17

Having picked up a Nikon Z6 just last weekend, I can tell you this: It's amazing how light it is, and in every spec and test I've been able to find, or run myself, it outshines the Sony A7 III. And the weight and dimensions are identical to the Z7 (the tradeoff between the two being that the Z7 has a higher mp, but slower max FPS, and the Z6 has a smaller mp, but faster FPS).

I've been shooting with it for only about a week now, and the gigantic upgrade over my Nikon d800 is readily apparent every minute I'm using it.

  • 3
    \$\begingroup\$ This doesn't seem to answer the question which is about finding a compact full-frame mirrorless camera. \$\endgroup\$
    – Philip Kendall
    Nov 21, 2018 at 20:37
  • 1
    \$\begingroup\$ @PhilipKendall they seem to be indicating that the Z6 is one. That answers the question. \$\endgroup\$
    – AJ Henderson
    Nov 25, 2018 at 21:14
  • \$\begingroup\$ @PhilipKendall - It exactly answers the question, "What do you think about this? Are any valid alternatives for what I am looking for?" - The Nikon Z6 is a full frame, mirrorless camera. And it's absolutely stunning. \$\endgroup\$
    – PKD
    Nov 28, 2018 at 23:01

Canon has just announced the new Canon EOS RP mirrorless camera last month. It’s the smallest and lightest full-frame EOS camera ever made.

the EOS R measures 5.3×3.9×3.3in (135.8×98.3×84.4mm) and weighs 23.2oz (660g).


I think the combination of these three might get close to being compact, full frame and mirrorless:

  • Canon EOS RP, $1300, 485 g
  • RF-EF adapter, $100, 125 g, 24mm
  • Canon 40mm f/2.8 pancake lens, $180, 130 g, 23mm

Total weight 740 g; not sure if you call that "compact".

Unfortunately, there doesn't seem to be a native RF mount pancake lens. Some day, I guess, such a lens will become available, and that day you could say there's a compact full frame mirrorless camera.

If you accept APS-C, the two will be lightweight and compact:

  • Canon EOS M100, $450, 302 g
  • Canon 22mm f/2 pancake lens, $230, 105 g, 24mm

Total weight 407 g. But, that is not full frame.


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