Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-13-2018, 10:12 AM - 1 Like   #31
Pentaxian
Class A's Avatar

Join Date: Aug 2008
Location: Wellington, New Zealand
Posts: 9,947
@rdenney
I agree with a lot of you what you said. One point, though:

QuoteOriginally posted by rdenney Quote
As said above, short primes don’t need to be as retrofocus with the short registration distance of mirrorless cameras.
There is an issue with lenses that attempt to push the short registration property, though.

In the era of film, a wide-angle lens could afford to hit the emulsion with very oblique angles. The emulsion responded nevertheless. Digital sensors, however, require light rays to enter sensels at a far more restricted family of angles. Microlenses can be offset to account for the outer areas of a sensor to be hit at more oblique angles than the centre area but one can only compensate for a limited amount as many lenses will hit the sensor with a rather moderate spread of angles. Software can be used to compensate for the colour failure of lenses that lack telecentricity but I don't subscribe to software compensation of hardware weaknesses.

Therefore, the "ultra small wide-angle that doesn't require a retrofocus design " remains a delusional fantasy of some MILC aficionados given the current sensor technology in which telecentricity requirements enforce retrofocus designs regardless of whether or not there is a mirror-box distance to bridge.

I'm not saying there is no focal length that allows a smaller lens to be designed for a MILC camera, but the case for small wide-angle lenses is often overstated. Besides, the size of a lens is predominately determined by how "fast" it is, as opposed to its registration distance. If one wants the same range of f-stop control then the lenses are going to have very similar size and weight.

04-13-2018, 10:17 AM   #32
Pentaxian




Join Date: Dec 2011
Posts: 2,066
Original Poster
QuoteOriginally posted by rdenney Quote
Does CIPA include fixed-lens digicams in their definition of DSLM?
No.

They report on ILC and then split it:
QuoteQuote:
Interchangeable lens cameras are broken down into Single lens reflex (cameras) and “Non-reflex” (cameras).“Non-reflex” includes cameras such as so-called mirrorless cameras and compact system cameras, rangefinder cameras with interchangeable lens and interchangeable unit system cameras, and similar cameras.
04-13-2018, 10:43 AM   #33
SMC PENTAX LENSES
Loyal Site Supporter
monochrome's Avatar

Join Date: Mar 2008
Location: St. Louis, Missouri
Photos: Gallery | Albums
Posts: 23,404
QuoteOriginally posted by beholder3 Quote
No.

They report on ILC and then split it:
You gave a well-designed trend analysis presentation that accurately depicts in chart form the decline in DSLR units over a representative long period, contrasted with a comparatively flat uptake of DSLM units over the same period. While it is risky to extend historical trends far into the future, to ‘call’ changes of trend direction in advance, and to infer causal product mix changes underlying the trends without sample data to support the inference, it amuses me the lengths observers will go in order to justify an interpretation of what is quite obviously presented before their very eyes.
04-13-2018, 11:21 AM - 3 Likes   #34
Site Supporter
Site Supporter




Join Date: Feb 2018
Location: NoVA
Posts: 395
QuoteOriginally posted by Class A Quote
@rdenney
I agree with a lot of you what you said. One point, though:


There is an issue with lenses that attempt to push the short registration property, though.

In the era of film, a wide-angle lens could afford to hit the emulsion with very oblique angles. The emulsion responded nevertheless. Digital sensors, however, require light rays to enter sensels at a far more restricted family of angles. Microlenses can be offset to account for the outer areas of a sensor to be hit at more oblique angles than the centre area but one can only compensate for a limited amount as many lenses will hit the sensor with a rather moderate spread of angles. Software can be used to compensate for the colour failure of lenses that lack telecentricity but I don't subscribe to software compensation of hardware weaknesses.

Therefore, the "ultra small wide-angle that doesn't require a retrofocus design " remains a delusional fantasy of some MILC aficionados given the current sensor technology in which telecentricity requirements enforce retrofocus designs regardless of whether or not there is a mirror-box distance to bridge.

I'm not saying there is no focal length that allows a smaller lens to be designed for a MILC camera, but the case for small wide-angle lenses is often overstated. Besides, the size of a lens is predominately determined by how "fast" it is, as opposed to its registration distance. If one wants the same range of f-stop control then the lenses are going to have very similar size and weight.
Yes, though newer sensors are better about oblique entry than older sensors. But I did say they didn't require as much retrofocus. So, a lens that is, say, half the focal length of the sensor diameter can be designed over a continuum. At one extreme, we have the opposing retrofocus design, such as a Schneider Super Angulon or Rodenstock Grandagon, both of which explore the double-Biogon concept. The lenses are distortion-less--the opposing groups offset each other's disortion. But they come very close to the image plane and work to a shallow angle with light rays hitting the surface, especially at the extremes. But they also project quite a round aperture into the corners, so the falloff is far less than would be predicted with a simple lens model. For example, a Super Angulon 47/5.6 comes very close to the film. Few lenses for small cameras have this design, and it's one reason architecture photographers still love them on large-format film, even if they no longer use film because of economics.

At the other extreme are strong retrofocus designs. The concept is a reversed telephoto, where the magnifiers are at the front to de-magnify the image coming into a central lens cluster of something like a gaussian design. The glass is well in front of the rear optical node, which is what determines the effective focal length. But that central cluster has to be very far in front of the rear node to clear the mirror box. A 45mm P67 lens has a rear node not even halfway to the lens mounting flange. The more retrofocus the design, the larger and more curved the front elements need to be--just look at the 645-DFA 25 or any 14mm lens for 24x36. This is expensive and difficult, and was made much more possible by aspherics and multi-coatings. Early extreme wides on SLR's required compromises--I recall (but without specifics) one early Nikkor ultrawide that required one to lock up the mirror, and the dedicated 38mm Biogon used in the Hasseblad Super-Wide Camera (SWC) didn't even have a mirror box. Both projected lens elements back where the mirror would normally be.

A mirrorless camera can take the middle ground. It needs enough retrofocus to spread an image behind it that can be corrected using what might be thought of as a teleconverter to project the rays straighter onto the sensor, but it doesn't need as much retrofocus as would be needed to clear a 70+mm flange distance. Hence, the 23 for the Fuji GFA-50 doesn't need to be as bulky or bulbous (or as expensive and hard to produce) as the DFA 25. It was smart of Fuji to target that focal length--it's the one real weakness in the Pentax 645 lens lineup.

Rick "not seeing much damaging falloff from the Pentax wides on the 645z" Denney

04-13-2018, 04:25 PM - 2 Likes   #35
Pentaxian
photoptimist's Avatar

Join Date: Jul 2016
Photos: Albums
Posts: 2,876
The Sony a7iii sensor stripe issue (Sony A7III with sensor stripe issues? - PentaxForums.com) suggests that sensors with integrated PDAF have a bigger problem with oblique rays than just a bit of vignetting. And knowing that the design of PDAF depends on segmenting light by angle, it seems inevitable that the design would have some trouble or reduced performance with any lenses with an unusual exit pupil distances or sizes.

As attractive as on-sensor PDAF seems, I can't help but think it creates compromises both to the main image and PDAF. Of course, maybe it's just like the compromises created by having a mirror. Both architectures have technical downsides and makers of both architectures labor mightily to mitigate those downsides.
04-13-2018, 08:37 PM - 1 Like   #36
Loyal Site Supporter
Loyal Site Supporter
clackers's Avatar

Join Date: Jul 2013
Location: Melbourne
Photos: Albums
Posts: 12,131
QuoteOriginally posted by photoptimist Quote
The Sony a7iii sensor stripe issue (Sony A7III with sensor stripe issues? - PentaxForums.com) suggests that sensors with integrated PDAF have a bigger problem with oblique rays than just a bit of vignetting. And knowing that the design of PDAF depends on segmenting light by angle, it seems inevitable that the design would have some trouble or reduced performance with any lenses with an unusual exit pupil distances or sizes.

As attractive as on-sensor PDAF seems, I can't help but think it creates compromises both to the main image and PDAF. Of course, maybe it's just like the compromises created by having a mirror. Both architectures have technical downsides and makers of both architectures labor mightily to mitigate those downsides.
Of course, that Fuji won't have the stripe issue, but it misses the mirror of the 645Z and will have lousy autofocus.
04-13-2018, 10:33 PM   #37
Pentaxian
Class A's Avatar

Join Date: Aug 2008
Location: Wellington, New Zealand
Posts: 9,947
QuoteOriginally posted by photoptimist Quote
The Sony a7iii sensor stripe issue (Sony A7III with sensor stripe issues? - PentaxForums.com) suggests that sensors with integrated PDAF have a bigger problem with oblique rays than just a bit of vignetting.
I haven't looked into this topic much myself but came across an investigation that demonstrated that the two images that can be obtained separately from one sensor with an on-sensor PDAF design are not that usable on their own. They need to be combined to cancel out each others imperfections for any application with expectations towards image quality.

This suggests to me that on-sensor PDAF is not a free lunch. Of course, we don't hear about potential disadvantages from D(umb)P(eople)Review.

P.S.: I'm not proud of how I am referring to DPReview and I'm not suggesting that their readers are dumb. I maintain, however, that the recent course DPReview has taken, with publishing many often ill-researched click-bait articles, is targeting an uninformed reader who lacks any capacity for critical thinking. Hence the name. I furthermore hope I can bring myself to not using the name anymore soon but when one of their staff accuses me of "trolling" just because I dared to point twice (in two separate comments to two separate articles) to an interview Nikon has given at CP+ 2018, it is hard not to be disappointed in DPReview. Apparently said member of staff thought my pointers to this interview flew too much in the face of his explanation attempt as to why Nikon had declined an interview request by DPReview for CP+ 2018. The idea put forward was that (paraphrasing) "Nikon did not send the right staff because they had nothing new to present".
04-14-2018, 03:53 AM - 3 Likes   #38
Site Supporter
Site Supporter




Join Date: Mar 2009
Location: Gladys, Virginia
Photos: Gallery
Posts: 19,122
I am inclined to think that some, at least, of the "smaller lenses for mirrorless cameras" mantra comes from the fact that they heavily use in camera lens profiles to manipulate sub optimal lens design into acceptable photos. I don't know that there is anything wrong with that, although if you have a lens that has 3 EVs of vignetting in the corners and the camera bumps that up, you will see noise pop up a lot quicker, even if you think you are shooting at low isos.

In general, I have no idea why there is such strong feeling among mirrorless proponents that SLRs will go away -- need to go away. This really isn't a VHS versus DVD situation where mirrorless cameras bring some sort of unprecedented technology to bear on photography. These cameras use the same sensors and have quite similar specifications. I really have not seen images created by Sony/Fuji/Olympus cameras where I thought, "Wow, that's amazing. Now you definitely couldn't have taken that photo with an SLR!" My expectation would be that both styles of camera will stick around for quite awhile. Probably not forever, but then again, none of us knows what style of camera we'll be shooting in ten years anyway.

In the meantime, I will continue to appreciate photos -- regardless of the style camera they have been taken with. Because that's really the point of photography -- images and achieving your vision.

04-14-2018, 07:12 AM   #39
Pentaxian
rangercarp's Avatar

Join Date: Oct 2012
Location: Southern Michigan
Posts: 386
QuoteOriginally posted by rdenney Quote
The digital Rebel DSLR or 5D they bought a decade of more ago still works.
QuoteOriginally posted by rdenney Quote
Any time there is a sea change in technology, there is a buying bubble as people replace obsolete stuff. Now that changes are becoming evolutionary rather than revolutionary, the bubble is deflating.
Well said. The upgrade cycle has stretched out a lot, and current sales are not an accurate representation of current user base.
04-14-2018, 10:08 AM   #40
Pentaxian




Join Date: Jan 2015
Location: mid nth coast,nsw
Photos: Gallery
Posts: 3,923
QuoteOriginally posted by Rondec Quote
none of us knows what style of camera we'll be shooting in ten years anyway.
Yes, however,the rate of advancement in smartphones will determine this.Samsung read the market and switched their resources.

Dedicated camera companies have a following at this point, but 5 years is a long time in the fast moving tech world,let alone 10.
04-15-2018, 07:03 AM - 3 Likes   #41
SMC PENTAX LENSES
Loyal Site Supporter
monochrome's Avatar

Join Date: Mar 2008
Location: St. Louis, Missouri
Photos: Gallery | Albums
Posts: 23,404
QuoteOriginally posted by surfar Quote
Yes, however,the rate of advancement in smartphones will determine this.Samsung read the market and switched their resources.

Dedicated camera companies have a following at this point, but 5 years is a long time in the fast moving tech world,let alone 10.
The ergonomics of the smartphone will never be satisfactory. It is a physical impossibility.
04-15-2018, 07:20 AM - 1 Like   #42
Pentaxian
photoptimist's Avatar

Join Date: Jul 2016
Photos: Albums
Posts: 2,876
QuoteOriginally posted by monochrome Quote
The ergonomics of the smartphone will never be satisfactory. It is a physical impossibility.
Exactly!

Moreover, the optical physics of the smartphone will never be satisfactory. That's also a physical impossibility.
04-15-2018, 07:27 AM - 1 Like   #43
Pentaxian
Site Supporter
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 31,349
QuoteOriginally posted by mecrox Quote
Have you done a similar one for revenue? At the end if the day it’s all about money and margins. For example, fewer items at higher prices may (or may not) be financially more attractive than more items at lower prices.
This is simply about who is using what. Not everything is about money. especially at the end of the day, when it's all about "what did you accomplish?"
04-15-2018, 07:57 AM   #44
Pentaxian
mecrox's Avatar

Join Date: Apr 2009
Location: Oxford, UK
Photos: Gallery
Posts: 2,347
QuoteOriginally posted by normhead Quote
This is simply about who is using what. Not everything is about money. especially at the end of the day, when it's all about "what did you accomplish?"
For the investors behind Canon, Nikon, Ricoh et al, it’s all about the money. It always has been. Neither just the units nor just the revenue gives the full picture. One needs both. The future of the camera market will be decided by the new middle classes in Asia. Their preferences will determine where the R&D spend goes. Simple as that.
04-15-2018, 08:16 AM   #45
Pentaxian
Site Supporter
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 31,349
QuoteOriginally posted by mecrox Quote
For the investors behind Canon, Nikon, Ricoh et al, it’s all about the money. It always has been. Neither just the units nor just the revenue gives the full picture. One needs both. The future of the camera market will be decided by the new middle classes in Asia. Their preferences will determine where the R&D spend goes. Simple as that.
My millionaire childhood friends who ended up with about 60 million inherited start up capital just sit in their office and make piles of money moving money around. They don't produce a thing.

Ricoh is in the camera business because their CEO wanted to be. There are easier ways to make money. There is nothing more cynical than "it's all about the money" Companies like Pentax, Canon and Nikon are all about assembling teams of engineers who want to make cameras. The money is an issue, if an only if they aren't making enough of it.

Just because you have this jaded "money is everything" view of the world doesn't mean it's relevant to everyone. Money can become an issue if you aren't making enough. Until then, it's just people trying to make great cameras at the best price, and making habit of money doing it.

We can assume that all the companies currently still making cameras are making enough money to concentrate on product and price point. How do you know money is an issue and is influencing decisions? When a company files for bankruptcy and is taken over by a court appointed accountant. Then you can assume it's all about money.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
cameras, canikon, canon and nikon, cipa, cost, data, dslm, dslr, market, milc, money, overview, pentax, people, photo industry, photography, product, ricoh, sales, time, units, volume
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K-5 vs MZ-S vs LX vs PZ-1p vs ist*D vs K10D vs K20D vs K-7 vs....... Steelski Pentax K-5 2 06-28-2017 04:59 PM
Pentax DSLR model comparison overview table beholder3 Pentax DSLR Discussion 17 02-20-2017 02:21 PM
Pentax DSLR flash options overview table beholder3 Flashes, Lighting, and Studio 11 02-04-2017 03:53 AM
O-GPS1 and your EXIF data - When the GPS is on, it strips data from the EXIF? Sagitta Troubleshooting and Beginner Help 17 11-23-2016 02:25 AM
BEWARE OF GULF DATA ELECTRONICS OR GULF DATA SYSTEMS Web Site stl09 Photographic Technique 2 09-29-2009 11:03 PM



All times are GMT -7. The time now is 05:46 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top