What wide-angle lens for MFT?

Question

I bought a Panasonic Lumix GX1 with the idea of using it for indoor wide angle shots for real estate. Obviously, I didn't realize what I was getting into. My little point and shoot Lumix takes wider shots than my 4/3 12-50mm lens. I also have old Canon lenses and bought the adapter, but I still don't have the right lens. Now I have 5 lenses, but none giving me the wide angle my point & shoot has. Can anyone tell me what lens I need, either 4/3 or old Canon, to give me this wide angle without much distortion? An inexpensive lens is fine if it works.

Lumix GX1

Lumix 24mm point and shoot

Answer 1

Here's three possibilities I can think of, in order of increasing grasping at straws. However, we only have your subjective impression to go on, and that's kind of vague, so I can't really weigh in meaningfully on whether this is enough to explain the difference you're seeing.

Maybe it's distortion correction?

I'm assuming you have the Olympus M.Zuiko Digital ED 12-50mm f/3.5-6.3 EZ, but the same could apply to many Micro Four Thirds lenses.

This system is designed with the idea that compromises in lens design can be compensated for with software. That means that many Micro Four Thirds lenses have very strong geometric distortion ("barrel distortion" at the wide angle, as opposed to perspective distortion — see this for more). This distortion is corrected for in RAW conversion by warping the image, and this would leave the edges not a rectangle and looking pretty bad, so it's normal to crop when doing so.

This could reduce the effective field of view noticeably from the 71.6 horizontal degrees that pure math would suggest.

Maybe you have a wide-angle converter on the P&S which you don't remember?

Something like this — an add-on optic that increases the field of view by 0.45× (that is, makes it about 2.2× wider). These are generally terrible for technical image quality, but may be sufficient for low-res real-estate pictures. (Although I'd hesitate to use any such thing professionally!)

Maybe the zoom ring on your camera is broken?

Maybe it turns to 12mm, but has some breakage or obstruction?

Please post examples!

... because otherwise, it's really hard to do more than guess.

Answer 2

OK, there have been some good suggestions made so far, and here are mine. Firstly, if you are doing a lot of wide angle shots, seriously consider getting a dedicated lens (or two) which will give you the coverage you need. Secondly, there are at least two cheap options which will give you good to excellent results. This is based on my own experience with Olympus, but should be very similar with the GX1.

Option 1 is the Samyang 7.5mm 3.5 lens, which is a (15mm equivalent) fisheye (180 degrees diagonal), but with near-stereographic projection. Sharpness is excellent in the center, and very good in the corners, probably the best you will get in a fisheye. With software de-fishing (Photoshop, Lightroom, RawTherapee etc), you can have straight lines and the look of a really wide lens. It does require some practice, and placing your focal point in the right place to minimise distortion. Manual focus and aperture only, but you can generally set it to f4-5.6 and infinity focus, unless you want to get really close. Very small and light, ~200g.

Option 2 is to use a Sigma 10-20 4-5.6 lens. Rather than try to find the 4/3 version and use an MMF-3 adapter, get a Canon (EF) mount, easy to find cheaply second hand. Viltrox make the EF-M2, an EF to m43 adapter with full electronic control (aperture, AF etc) for about $150 US. This is a "speedbooster", which acts like a teleconverter in reverse. The 10-20 lens then becomes a 7-14 2.8-4 lens, so a 14-28 lens on the GX1 (actually shows up in camera as a constant f3.1 lens, but whatever). I have this combination, and it is very sharp, corners are excellent, and there is minimal vignetting (dark corners). Much cheaper than an Olympus or Panasonic 7-14 lens, for example, and nearly as good. Bigger and heavier, ~500g

Viltrox also make an EF-M1, which is the same thing without any optics for about $50 less. This would give you a 20-40 4-5.6 equivalent lens. The only downside is that you may need to "tweak" the EF-M2 to get it to AF to infinity due to the optics, but I can take you through the process if need be.

The 12-50 is a good lens, but it is not really wide enough for what you do.

Final point - do your real estate pics need to be architecturally accurate, or is it more important to get as much into the image as possible?

Hope this helps.

Answer 3

Unless you have a lens with an imaging circle that does not fully cover the sensor (eg a lens designed for 8mm film cameras), the focal length (the "x mm" number) determines the angle of view you are getting at a given sensor size.

The "old Canon" lenses are likely adaptable full-frame lenses. 12mm (as your MFT zoom lens has) is already an extremely low focal length for full frame - rectilinear wideangles at 12mm and below for full frame are exotics, and will come at an uneconomical price even if bought second hand. Vintage full frame lenses can save you a lot of money when it comes to extreme telephoto ranges (if you can live with manual focus, size and weight), but will rarely help in the extreme wideangle range.

Your 12mm are equivalent to a 24mm full frame lens - 24mm is considered the longest "ultra wideangle" length in full frame, even a 24mm lens for a fullframe camera is almost an exot.

For MFT, in 2018, it seems that the shortest rectilinear options are also expensive - see the Laowa 7.5mm (15mm full frame equivalent) or Samyang 10mm (20mm full frame equivalent).

There are cheap so called "wide angle converters", but they either do not even try to be rectilinear or aren't good at it.

There are cheaper fisheye (non rectilinear) options at 6.5mm and 7.5mm available, but you would need to correct the distortion in software, losing some resolution and image fidelity in the process.

What could be useful for your purposes is the Sigma 10-20mm (or 8-16mm, but this one tends to be expensive too..) zoom (would need to be adapted, and will be manual focus! The "four thirds" version will not fit an MFT camera. Do not try adapting the Canon version, unless you have a very expensive/exotic adapter you will have no aperture control - adapting from Sony A, Pentax or Nikon is your best bet here...) , or the Olympus 9-18mm (native MFT, expensive).

Fisheye effects are great for art, they are not helpful in documentary architectural photography...

BTW, some technical background: P&S cameras can easily incorporate rather brutal wide angles for three reasons. First, the rear element of the lens can be placed obscenely close to the sensor, simplifying lens design. Second, the sensor can be optimized to deal with a lens closed to the sensor and covering it with a small exit pupil. Third, you can leave all sorts of lens errors in place and correct them in software and in camera - since there is no non-hackish way to even test the lens off the camera, you do not run the risk of reviewers bad mouthing your lens for being an optical catastrophe. That way, the wide angle mode on a P&S can actually be a heavily vignetting fisheye optically.

By the way, even some kit zooms for DSLMs already use electronic correction heavily (there is firmware in the lens telling the camera what to do).

Answer 4

That's the strange part. I set up both cameras on a tripod, shooting into a room. I used the point and shoot, a Panasonic DMC-ZS19, and the 4/3 panasonic Lumix GX1. There was no doubt that the point and shoot had a much wider angle of view.(It says Leica 24mm WIDE on the outside).

What you need to understand is that the 4/3 sensor in your new camera is a lot smaller than a "full frame" sensor, and that means that it won't "see" a lot of the image that's projected by the Canon lenses you're using, so the angle of view in your images will be less than you'd get with the same lens on a full frame or even a crop sensor camera. I think that your 4/3-format camera has a crop factor of 2.0, meaning that it's view of the world through a given lens will be similar to that of a full frame camera using a lens of twice the focal length. In other words, if you put your Canon 50mm lens on your Lumix 4/3 camera, you'll get an image similar to what a full frame camera would produce using a 100mm lens. Or, if your point-and-shoot gives you the equivalent view as a 24mm lens on a full frame camera, you'll need a 12mm lens to produce the same view on your 4/3 camera.

For your real estate work, you probably want what's called a rectilinear wide angle lens, meaning that it'll mostly keep straight lines straight. The alternative is a fisheye lens, which distorts the world the same way the peephole viewer in an apartment door does. If you want to match the 24mm-equivalent of your point-and-shoot you'll need a full frame lens with a focal length of 12mm, or else a 24mm-equivalent lens made for your camera.