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09-17-2016, 07:57 PM   #1
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Lens Size Comparison between Mirrorless and dSLRs

Here is an interesting article about lens sizes, in particular lenses using Sony's mirrorless cameras as a strawman...


09-17-2016, 11:36 PM   #2
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Very interesting article - worth the read
09-17-2016, 11:46 PM   #3
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Don't all those K-1 owner feel foolish knowing they've been fooled by Pentax' IBIS marketing ploy?
09-18-2016, 02:43 AM   #4
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Well, I think this is the sort of article that has questionable utility. Fuji has been trying to make the case for ages that full frame is useless and that image quality is close enough between full frame and APS-C to say that there is no real difference and you would have to jump up to medium format to really see a performance boost. Basically, though, they have painted themselves into a corner by (I guess) choosing a mount that isn't easily compatible with full frame and now saying that they are really happy in that corner.

Assuming the same size mount and roughly the same registration distance, lenses that are equivalent will be the same size. That is to say, a 55mm f1.4 on APS-C will be the same size as a 85mm f2 on full frame. But, if you shoot full frame, you can get a 15-30 f2.8 zoom, but there isn't anything like a 8-20mm f2 zoom available for crop cameras.

Anyway, long story short, overall, there is some benefit with lens/body size combined when shooting mirrorless as long as you are shooting primes that aren't too long. Once you get into zooms and telephoto lenses, SLRs and mirrorless options are pretty close in size.

And Fuji is awesome.

Just ask them.

09-18-2016, 04:18 AM   #5
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What I don't get is wasn't all that obvious to designers from the beginning?
A 300mm lens requires an actual physical light path from the objective to the focal plane of 300mm no matter what body is used?
Or to put it simplistically another way - a mirrorless 300mm lens is essentially a 300mm DSLR lens with an additional permanent extension tube added to the back end all else being equal. So what else is new?

The question that comes to my mind is what essential innate advantage/disadvantage does/does not the two systems have over one another?
It's hard for me to believe that Sony and Fuji went ahead with mirrorless development knowing there was no real advantage to the mirrorless system other than as a cynical marketing ploy.

Last edited by wildman; 09-18-2016 at 04:23 AM.
09-18-2016, 06:36 AM   #6
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QuoteOriginally posted by wildman Quote
The question that comes to my mind is what essential innate advantage/disadvantage does/does not the two systems have over one another?
It's hard for me to believe that Sony and Fuji went ahead with mirrorless development knowing there was no real advantage to the mirrorless system other than as a cynical marketing ploy.
Cheaper to produce= better profit , the rest is marketing
09-18-2016, 06:41 AM   #7
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QuoteOriginally posted by bobmaxja Quote
Cheaper to produce= better profit , the rest is marketing
That's too easy and simple-minded.
09-18-2016, 01:52 PM   #8
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QuoteOriginally posted by wildman Quote
...
The question that comes to my mind is what essential innate advantage/disadvantage does/does not the two systems have over one another?
It's hard for me to believe that Sony and Fuji went ahead with mirrorless development knowing there was no real advantage to the mirrorless system other than as a cynical marketing ploy.
DSLR has at least one significant advantage - you can frame pictures with the camera off, and even with the camera on, it uses much less battery.

MILC has two clear advantages, but I'm not sure how much these matter to most users:

(1) construction is simpler

(2) EVF gives more reliable view of what actual image will be like. As I've already said several times, I became acutely aware of that a couple of weeks ago when I was trying to take a picture with my K-30 in a very dark area. I could not see my subject clearly through the OVF, but framing was very easy under LV; however holding the camera using LV was awkward - and that issue would have gone away if I'd had an EVF.

My Q-7 has an additional advantage - it is so quiet - but that is true only because of its leaf shutter.

09-18-2016, 06:04 PM   #9
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QuoteOriginally posted by bobmaxja Quote
Cheaper to produce= better profit , the rest is marketing
QuoteOriginally posted by wildman Quote
That's too easy and simple-minded.
That's actually the real reason, especially given Sony's deep expertise in manufacturing process engineering. Invent a new technology - marketing then creates the demand for something we didn't know we wanted last month.

MILC has a significant manufacturing cost advantage over dSLR. What it doesn't have have is decades of embedded SLR engineering costs that are essentially free now, analogous to the internal combustion engine.

Electric or Hybrid is interesting, but the basic engineering of gasoline power is essentially known to all manufacturers and available at no R&D cost.
09-18-2016, 06:39 PM   #10
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QuoteOriginally posted by monochrome Quote
Invent a new technology - marketing then creates the demand for something we didn't know we wanted last month.
That exactly describes large scale industrial capitalism since Watts in the 1770s - this economic behavior is unique to contemporary MILC manufactures?

But in any case my question was not one of economic motive, good or bad, but one of the practical advantages, if any, over one or the other system either now or in the future for the ordinary photographer.

Last edited by wildman; 09-18-2016 at 06:52 PM.
09-18-2016, 07:37 PM   #11
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QuoteOriginally posted by wildman Quote
The question that comes to my mind is what essential innate advantage/disadvantage does/does not the two systems have over one another?
There are real advantages when it comes to AF accuracy and the ability to use facial recognition, Eye AF, and subject tracking that DSLRs manufacturers currently can't match. At the beginning of the wedding I will take a picture of the bride and program her face as priority #1, the Groom is #2. If there is a crowd the camera will find her face and lock focus and lock the eyes in focus if the light is half way decent. Its still not perfect technology but when it works you can work fast and get razor sharp pictures. All of this takes lots of processing power and sucks batteries dead at record speed. Mirrorless is still not perfected. It needs lots of processing power and lots of battery power.

For casual use I love the A7II with the 55mm F/1.8 lens. Its fast enough for most casual photography and the image quality is excellent. If it were any smaller it wouldn't fit my hands. The original A7 had terrible ergonomics for me. Fuji is in the same boat. By the time I add the grip to make it big enough for my hands, I might as well be using the K-1. Fuji does a lot of things right and I know a couple of people who have sold their Nikon, Canon, & Pentax gear to move to Fuji. They love the X-T1 and the Fuji lenses. There are a lot of things I love about the X-T1, but the IQ of the K-1 is noticeably better. I'm very interested in the new Fuji medium format.

QuoteOriginally posted by monochrome Quote
Invent a new technology - marketing then creates the demand for something we didn't know we wanted last month.
Which is why supply drives the economy. Nobody new they needed a blackberry or iPhone until they realized what they could do and how it would make their lives better (if used correctly). If they never invented the digital camera most of us would still be using film and dumping toxic chemicals down the drain in our basement darkrooms. Someone decided to build digital cameras and market them as being better than film and eventually most of us agreed.
09-18-2016, 07:39 PM   #12
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QuoteOriginally posted by wildman Quote
What I don't get is wasn't all that obvious to designers from the beginning?
A 300mm lens requires an actual physical light path from the objective to the focal plane of 300mm no matter what body is used?
Or to put it simplistically another way - a mirrorless 300mm lens is essentially a 300mm DSLR lens with an additional permanent extension tube added to the back end all else being equal. So what else is new?
That is not strictly true, lens designers have tricks to shorten or lengthen the lens relative to its focal length. My Sigma 150-500 is nowhere near 500mm (20 inches) even fully extended. My Sigma 8-16 is much more than 16mm (about 2/3 of an inch) long. For these lenses, though, the conclusion is still valid, the short register distance of a mirrorless camera is wasted.

QuoteQuote:
The question that comes to my mind is what essential innate advantage/disadvantage does/does not the two systems have over one another?
The big advantage for mirrorless is for lenses with a focal length larger than the registration distance of the mirrorless camera, but less than the registration distance of a DSLR. IIRC this is typically around 20mm to 40-something mm. This covers the traditional 135 film format wide angle range. A mirrorless lens in this range would not need to use the more complex "retro focus" formula, and it should be easier to produce a fully corrected lens with fewer elements, making it smaller and lighter.

But in reading that article, what struck me was not so much that FF 135 format lenses are necessarily big and heavy, but that high quality, fully corrected, fast "pro" lenses are necessarily big and heavy (for any format). That still makes the point that a FF 135 "pro" level mirrorless camera is not particularly attractive from a compactness perspective. Maybe for a back-packing landscape pro using 20-40mm lenses where speed and correction wide open is not as important and size/weight is critical.
09-18-2016, 07:49 PM   #13
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QuoteOriginally posted by Cthulhugan Quote
That is not strictly true, lens designers have tricks to shorten or lengthen the lens relative to its focal length.
That is what a Telephoto lens does. The focal length is longer than the actual length. This adds to the cost and complexity. The opposite is a lens like the 31mm LTD the register distance is greater than 31mm so it becomes a more expensive lens to produce and a larger lens than the 43mm which is very close to the register distance and thus is cheaper and smaller.
09-18-2016, 08:56 PM   #14
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QuoteOriginally posted by Cthulhugan Quote
That is not strictly true, lens designers have tricks to shorten or lengthen the lens relative to its focal length. My Sigma 150-500 is nowhere near 500mm (20 inches) even fully extended. My Sigma 8-16 is much more than 16mm (about 2/3 of an inch) long. For these lenses, though, the conclusion is still valid, the short register distance of a mirrorless camera is wasted.
I'm well familiar with this - it's the negative focus group on the back end of all true telephotos. Functionally all telephotos have a permanent built in TC for the purpose of shortening the physical length of the optics tube. Of course while it does shorten the length of the lens it also introduces it's own aberrations. In fact a so called 500mm "prime" telephoto is a contradiction in terms as it does not operate at prime focus but gives only an apparent focal length of 500mm. My simple 560mm APO triplet scope is a true prime focus glass for instance - nothing between the front objective cluster and the camera sensor but air.

Last edited by wildman; 09-18-2016 at 09:02 PM.
09-18-2016, 09:00 PM   #15
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QuoteOriginally posted by Winder Quote
That is what a Telephoto lens does. The focal length is longer than the actual length. This adds to the cost and complexity. The opposite is a lens like the 31mm LTD the register distance is greater than 31mm so it becomes a more expensive lens to produce and a larger lens than the 43mm which is very close to the register distance and thus is cheaper and smaller.
Exactly. Another example is a tele-converter, that adds elements to increase focal length. The total length does not increase as much as the focal length. The added elements have a cost in terms of image quality. That cost is greater for a tele-converter that must be generalized to work with any lens than when building it into the optic formula of a specific lens.
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