The relative merits of DSLRs and mirrorless

[Ilkka Nissilä]

It is not my impression that the photographers who need cold capable equipment is few.

Personally I do most of my nature photographs in the winter and especially those days when it is bitterly cold are photographically productive. This is because the snow looks different in those circumstances and there can be "sea smoke" coming out of open water that create interesting visual elements in the images. Ice crystals can also be interesting macro subjects themselves. I think a lot of landscape photographers who are familiar with these latitudes would find that these are some of the best of times to make images.

https://www.flickr.com/photos/ilkka_nissila/32767793816/in/dateposted-public/

Furthermore, I find that while I do not regularly photograph wildlife, the bitter cold days create opportunities where interesting wildlife photographs can be made due to the circumstances changing the behavior of the animals and their priorities.

https://www.flickr.com/photos/ilkka_nissila/38613108410/in/dateposted-public/
https://www.flickr.com/photos/ilkka_nissila/29886990273/in/dateposted-public/

[Akira]

The mp3 is relevant in two ways.

...

The mirrorless design is not favoured by the manufacturers for photographic reasons, but because more of its elements can be patented, so it suits a business model based on monetising intellectual property rights. It is not that the mirrorless design is bad for photography, but that the business model that is based on it is bad for photography in the same way as it is bad for music.

I didn't think about the camera or the data file formats from the patent point of view.  Your explanation makes sense.

[Akira]

Apparently we would still have to wait for a whole year...   

https://www.43rumors.com/new-competition-from-nikon-hitting-the-market-in-spring-2019/

[Frank Fremerey]

Speaking of hybrid systems: noone has yet developed a hybrid DSLR viewfinder which would be a dream come true for people like me needing strong reading glasses but not glasses at all in the far field.

With a hybrid VF I could check my captures immediately after the shot in my VF, like I do using the Fuji 100T set to OVF and image review. Chimping is a burden, because I have to find and adjust my reading glasses to use the display on the back, while the Camera VF is corrected by the Diopter settings.

[Ilkka Nissilä]

Speaking of hybrid systems: noone has yet developed a hybrid DSLR viewfinder which would be a dream come true for people like me needing strong reading glasses but not glasses at all in the far field.

Well it has been an area of study (and patenting) but the EVF insert would reduce the quality of the optical viewfinder image so it didn't make it into a product.

[Les Olson]

You could have two separate viewfinders, one real and one electronic.  If they were the right distance apart you could use them simultaneously.

[pluton]

I don't know if it is what you are referring to but there is a well-defined phenomenon of loss of vision in one eye caused by looking at bright screens in the dark (http://www.nejm.org/doi/full/10.1056/NEJMc1514294).

I assume that what folks call 'eye strain' is something painful.  I have not experienced pain from EVFs. I will not consciously do anything that causes pain to my eyes in order to use a camera...any camera, for any reason.
The experiment in the link describes 'Transient Monocular Vision Loss' caused by staring at a bright thing in a dark ambient condition. 
Using an EVF in daytime is staring at a dark thing in a bright ambient condition.
If I could walk through the world wearing dark sunglasses, and only take the glasses off when looking through the Fuji XE EVF, then the EVF would seem nice and bright.

[Akira]

Another concern of a mirrorless camera is the fully exposed sensor, especially when you have to change lenses under dusty or splashy conditions.  The tens of thousands of dollar digital backs are formidable in this regard.   

Cameras like New Mamiya 6 or Mamiya 7 had a shutter curtain that closes during the lens change.  Of course, that was to prevent the film from the exposure, but that could be applied to the mirrorless cameras in order to protect the image sensor.

Most of the mirrorless cameras have mechanical shutters.  I wonder why nobody has implemented this function.   

[Hugh_3170]

Akira, that was a concern of mine when I got my first Olympus E-M1 mirrorless camera. 

I now have two E-M1s and despite many many lens changes they have not so far picked up dust bunnies, whereas my DSLRs would have had their sensors buried in dust had they been exposed to the same levels of lens changing without sensor cleaning.  Maybe the lack of a mirror or perhaps less bellows effects with Olympus lenses or sensor coatings could be partial answers as to what I have experienced.  How are your Panasonics M43 cameras in this respect, as I understand that some of the Panasonic cameras use sensors from the same supplier?

[Akira]

Akira, that was a concern of mine when I got my first Olympus E-M1 mirrorless camera. 

I now have two E-M1s and despite many many lens changes they have not so far picked up dust bunnies, whereas my DSLRs would have had their sensors buried in dust had they been exposed to the same levels of lens changing without sensor cleaning.  Maybe the lack of a mirror or perhaps less bellows effects with Olympus lenses or sensor coatings could be partial answers as to what I have experienced.  How are your Panasonics M43 cameras in this respect, as I understand that some of the Panasonic cameras use sensors from the same supplier?

Hugh, I've used various m4/3 camears and DSLRs, and my experiences with both types of cameras are exactly the same as yours.  Even when I spotted some dusts, they could be easily removed using my HEPA JET blower with the exposed sensor facing downwards.  I would say that their anti-dust coating seem to work really well, and the dusts were not sticky.

On the other hand, the dusts on the sensor of DSLRs seems to be stickier than those of mirrorless cameras.  I would assume that the most of the dust bunnies on the sensor come from the mirror mechanism and they are oily.

Nevertheless, the fact that the sensors of mirrorless cameras are completely exposed persists.

As for the sensors of the Panasonic cameras, I believe they are produced in-house.

[Les Olson]

The experiment in the link describes 'Transient Monocular Vision Loss' caused by staring at a bright thing in a dark ambient condition. 
Using an EVF in daytime is staring at a dark thing in a bright ambient condition.

It depends whether the photographer closes the eye not at the viewfinder.  If the photographer closes the eye not using the EVF, it is the same as the published cases: one eye looking at a relatively bright screen and one in the dark.  If both eyes are open and the EVF is relatively dark, the sides are reversed, as it were, but there is still one eye dark adapted and the other not, so when both of them look at the same illumination the mis-match between the eyes is perceived as malfunction. 

Evidence against it being just the relative dullness of the EVF is that SLR viewfinders are also dull: if you look through the SLR viewfinder with a lens of f/4 maximum aperture the viewfinder is 1/64 as bright as the ambient light (not 1/16; image brightness = scene luminance divided by 4N^2 where N is relative aperture = F, so if N = 4 the image brightness is 1/64 of the scene luminance; as an aside this also tells you that the largest aperture a lens can have is f/0.5). 

[Ilkka Nissilä]

On the other hand, the dusts on the sensor of DSLRs seems to be stickier than those of mirrorless cameras.  I would assume that the most of the dust bunnies on the sensor come from the mirror mechanism and they are oily.

The D600 oil spot issue was caused by the shutter, not the mirror mechanism, as far as I know. I'm wondering which cameras do you see oily spots on?

Only in a few cases have I had sensor spots where they weren't removed simply by applying air flow (I used to use a blower but now a vacuum because the latter keeps the sensor clean for a longer time). I am not saying it's not possible to have oily spots but I just haven't run into them on cameras newer than the D3X (which doesn't have the sensor shaker). On the D3X I do see a few spots at smallish apertures but in my other cameras I find it rare to see a spot that sticks.

Blowing the dust tends to move it around in the mirror box and it may end up in the corners and when the mirror moves the air around they can reappear on the sensor at times. By using a vacuum they are removed permanently and this has been very effective for me, of course one has to be careful and I use the MIN setting and rest the tip of the vacuum against the bayonet to avoid accidents.

If I shoot in a dusty environment so that I notice some buildup around the lens mount I take the camera to be cleaned at service, but this is something I have had to do only a couple of times. Usually my own vacuum at MIN settings applied once a year does the trick. In my landscape camera, I usually shoot at f/9 to f/11, sometimes f/13 (for water flow) and I can't recall the last time I saw a spot in my landscapes in D8x0 cameras. I keep the automated sensor shaking on so that it is activated when the camera power is recycled. I have this habit of turning the camera off whenever I'm not actively shooting so this way the sensor actually gets a shaking quite often. 

[Akira]

The D600 oil spot issue was caused by the shutter, not the mirror mechanism, as far as I know. I'm wondering which cameras do you see oily spots on?

I've found dust spots on all DSLRs I've owned; two D7000s, a D610 and two D750s.  I said "oily" because the dusts couldn't be removed using HEPA JET blower (well, I should have said "sticky".).  On the other hand, the dust spots on the mirrorless cameras could be in general easy to be blown off with the HEPA.

[Ilkka Nissilä]

Ok, so the mirror mechanism could spill oil but the shutter is closed when the mirror is moving, so it would then land on the shutter and from there it would end up on the sensor. I suppose that is possible.

There may be a few spots that I haven't noticed in my newer cameras that might show up at f/22, it's just that in my normal shooting I haven't noticed any (except on the 2007/2008 cameras which didn't have dust shakers and the air flow design was different as well I believe). On the D3X, there are a few spots but on D800/D810/D850/D5 it has never been a problem.

I guess it is possible the oil spillage depends on the climate (temperature and humidity) or other factors that might explain why some have problems and others do not.

[Les Olson]

Oil has a refractive index of about 1.5 - the same as glass.  Because of surface tension a drop of oil forms a plano-convex lens shape on a sensor, so  it appears as a bright spot with a darker rim.  A dark spot is not oil.