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Focal plane vs. leaf shutters in MF SLRs



 
 
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  #51  
Old May 14th 04, 01:01 AM
Bob Monaghan
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Default Omega 120 surprise convertible lens RF? Focal vs. leaf


yes, the Omega 120 is one ugly camera ;-) So are my Koni Omega 6x7cm RF
and lenses, rather hard to pack cuboidal bodies, heavy, but very rugged
;-) The interchangeable inserts and magazines (my RO200 model) add to
flexibility, at modest weight. And the lenses are very good also, as Chris
Perez' tests suggest and many users have confirmed. Obviously, I don't
care a lot about camera appearance or the looks I sometimes get using mine
;-)

yes, the uncoupled rangefinder would probably work fine for many users,
esp. landscape types and a lot of travel work. A simple focusing chart
along the sliding standard (as with many older folders) could do the job
too, minimizing the cost and complexity of the focusing mount.

But you are probably right that our interest doesn't match the real
marketplace, so we will have to homebrew such cameras rather than expect
to run in and buy them off the shelf. I think if fuji had made their zoom
lens a bit longer, it might have been enough to make it a nice travel
camera (esp. at 28 ounces for a 645 RF).

I think a big part of the reason folders died, similar to TLR sales, is
that the existing market of used and low cost but serviceable TLRs and
folders made it possible to satisfy many buyers with a used rolleiflex or
ikonta or whatever. Even today, many folks are settling for a Moskva 5
copy or similar at modest prices, and happily so if they get a good one
;-) But the lack of a multiple lens option makes these cameras less of a
stand-alone solution for travel and so on, making the Bronica RF645 and
Mamiya 7 series a lot more attractive to users.

I have been playing with a few polaroid SLRs, captiva etc., and keep
trying to think how a MF rollfilm folder could be similarly crafted.
Another area of inquiry is how a digital chip could be used in a modern
design for focusing and composition (including closeup work as with SLR)
and then pop out of way and allow film exposure. This would eliminate much
of the SLR bulk and complexity while providing thru the lens composition
and effects (grad filters, polarizers..) etc.

Finally, it may just be that we need better afocal adapters. As I have
noted, the telephoto (finder scope style) attachments could be used easily
enough in a pinch with the right bayonet filter ring adapter (faster
on/off). A low magnification afocal adapter should be do-able with minimal
vignetting, though size and close focusing distances would be tradeoffs...

The zeiss mutars were very pricey but also very excellent adapters. The
standard japanese/korean superwide 0.42x and similar are not close to the
cost or quality, though pretty good for the $$. Perhaps some of the new
lighter superwide adapters for video will be better optically, and so
provide an option for fixed lens camera users (moskva 5 etc.?). The one I
have purchased is not as good as the bigger heavier glass older 0.42x
mutar I matched it against, but then, what can you expect for $20-ish from
dealer closeouts? ;-)

oh well, the search for the perfect camera, as with the perfect
cheeseburger, continues...

grins bobm
--
************************************************** *********************
* Robert Monaghan POB 752182 Southern Methodist Univ. Dallas Tx 75275 *
********************Standard Disclaimers Apply*************************
  #52  
Old May 14th 04, 01:19 AM
Bob Monaghan
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Default Focal plane vs. leaf shutters in MF SLRs


the wink light is okay in the 3 to 12 foot or so range, provided you can
find the 45 volt batteries etc., but lots of us shoot with slower films
and at distances beyond 12 feet...

There are some sophisticated camera/flash combos in 35mm which provide a
series of short flash pulses during exposure in a similar manner to the
wink light, but here again, light levels are limited as flash tubes heat
up, even if you solve all the timing (read as avoiding banding) issues ;-)

unfortunately, extended focal plane flash bulbs are available from only a
few sources new, and quite pricey.

this is getting to be less of an issue, as focal plane flash synch speeds
continue to increase, but then leaf shutters have also gone up in speed
too (e.g., PQS rollei 6x6cm leaf shutter lenses at 1/1000th second flash
synch speeds). I have used nikon kits with a nikkormat backup body just
because the flash synch speed was almost a stop faster than the pro F
bodies.

The big problem for MF focal plane users is so many MF cameras have flash
synch speeds around 1/60th second, making ghosting in daylight shots
(e.g., weddings outdoors) problematic with many film choices ;-( Older
cameras may be even worse, down to 1/30th second (yeech).

The other issue is reliability. Camera MTBF for focal plane camera bodies
is almost entirely determined by shutter failure rates. Having leaf
shutter lenses (plural) means when the shutter in one lens fails, you can
still keep shooting with the other lenses. Yes, maintenance costs and
purchasing costs are higher, but the extra margin of reliability may be
worth it.

Still, the flash synch range for leaf shutters is really their big selling
point, IMHO ;-)

grins bobm


--
************************************************** *********************
* Robert Monaghan POB 752182 Southern Methodist Univ. Dallas Tx 75275 *
********************Standard Disclaimers Apply*************************
  #53  
Old May 14th 04, 08:04 AM
Lassi Hippeläinen
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Default Focal plane vs. leaf shutters in MF SLRs

Jim-Ed Browne wrote:

At the risk of flogging a long-embalmed horse-hey, thirty million
Elvis and MM fans can't be wrong!-I think flash sync for daylight is
an issue best solved by longer-duration flashes, such as perhaps an
updated variant of the old Polaroid Wink-Light, which pulsed an
incandescent bulb with a cap and high-voltage battery. I can't believe
it would be that hard to build one today, perhaps using a triac to
limit the current to the triggering camera. Doesn't anyone have basic
electronic skills anymore?


Now that phone cameras with built in flashes made of LEDs start
appearing, it might be interesting to experiment with a LED-based
winklight...

-- Lassi
  #54  
Old May 14th 04, 07:14 PM
Gordon Moat
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Default Omega 120 surprise convertible lens RF? Focal vs. leaf

Bob Monaghan wrote:

. . . . . . . . . .

yes, the uncoupled rangefinder would probably work fine for many users,
esp. landscape types and a lot of travel work. A simple focusing chart
along the sliding standard (as with many older folders) could do the job
too, minimizing the cost and complexity of the focusing mount.


It is actually a little surprising how accurate one get become using just an
uncoupled rangefinder, and a somewhat calibrated focus scale. While I am sure
distance and DOF help in most cases, I have also done many successful, well
focused, images at close range use folder cameras. One area that has been
less successful is accurate framing, since these cameras do not offer
parallax correction.



But you are probably right that our interest doesn't match the real
marketplace, so we will have to homebrew such cameras rather than expect
to run in and buy them off the shelf. I think if fuji had made their zoom
lens a bit longer, it might have been enough to make it a nice travel
camera (esp. at 28 ounces for a 645 RF).


I really wonder about the longer focal length, or telephoto usage. While many
seem to want longer lenses, I question how much they actually get used.
Combine that with larger film sizes, and cropping ability, and I do not think
the Fuji rangefinders sold poorly due to lack of long lenses. While that
might be claimed for the Bronica RF645, I think the real story is distrust
due to the focusing problems with the early 135 mm lens.

Many medium format (645 or 6x6 mostly) photographers will claim using a 150
mm lens often. When looking at what these are most useful for, it is often
tight framing for portraits, either head shots, or only head and shoulders
(upper torso) images. While a longer lens can be less obtrusive to your
subject, by allowing more distance, I really wonder about the desire to
always fill the frame. With 6x6 photographers especially, most of the square
images get cropped anyway, so what is the big deal about cropping further.



I think a big part of the reason folders died, similar to TLR sales, is
that the existing market of used and low cost but serviceable TLRs and
folders made it possible to satisfy many buyers with a used rolleiflex or
ikonta or whatever.


Victims of their own success? Perhaps they should have made them of worse
quality, which would ensure future sales.

Even today, many folks are settling for a Moskva 5
copy or similar at modest prices, and happily so if they get a good one
;-) But the lack of a multiple lens option makes these cameras less of a
stand-alone solution for travel and so on, making the Bronica RF645 and
Mamiya 7 series a lot more attractive to users.


Though the Bronica RF645 has not sold well. A check of used prices for Mamiya
7, and many not completed auctions, might indicate that the price for the
Mamiya is thought to be too high. Don't get me wrong, I think these are great
systems, though I think the marketing and further development could go
better. I hope neither of these companies discontinue these cameras.

I am really amazed that you never mentioned the Polaroid 600SE. There were
roll film backs, and a few lenses available. While not super light, it is
somewhat compact. The rangefinder works fairly well, though the left hand
grip takes a little getting use to using.



I have been playing with a few polaroid SLRs, captiva etc., and keep
trying to think how a MF rollfilm folder could be similarly crafted.


The focusing mechanism on the Automatic 250, 350, 360, and 450 is one very
useful item. Removing that and attaching to a flat adapter plate for
something like a Graflock, Linhof, Horseman, or similar roll film adaptation,
would be useful.

I saw a somewhat rare NPC item once that might get your interest. It had a
Copal 3 shutter, with a Nikon F mount on it. Just a simple aluminium block
was used to locate all the parts, and a pack film back. I would think that
something similar could be done using other lens mounts, and large format
shutters. I don't remember the focusing mechanism for that, though it would
seem that something could be adapted.


Another area of inquiry is how a digital chip could be used in a modern
design for focusing and composition (including closeup work as with SLR)
and then pop out of way and allow film exposure.


You mean something other than a removable back, like some medium format
backs? I think one problem is that these are a bit thick, so your eye goes
further back than with the normal film back, except on some SLRs.

This would eliminate much
of the SLR bulk and complexity while providing thru the lens composition
and effects (grad filters, polarizers..) etc.


Still seems like a simple ground glass would work okay. Personally, I think
it is a shame that a truly small and compact TLR was not developed, where the
focusing lens and mechanism where closer to rangefinder size, and got away
from the box shape.



Finally, it may just be that we need better afocal adapters. As I have
noted, the telephoto (finder scope style) attachments could be used easily
enough in a pinch with the right bayonet filter ring adapter (faster
on/off). A low magnification afocal adapter should be do-able with minimal
vignetting, though size and close focusing distances would be tradeoffs...


There are Optec, Raynox, and Century Precision, though mostly video and
motion film cameras. I have used some Century Precision adapters, and they
are very high quality, though at a somewhat unfriendly price.


The zeiss mutars were very pricey but also very excellent adapters. The
standard japanese/korean superwide 0.42x and similar are not close to the
cost or quality, though pretty good for the $$. Perhaps some of the new
lighter superwide adapters for video will be better optically, and so
provide an option for fixed lens camera users (moskva 5 etc.?). The one I
have purchased is not as good as the bigger heavier glass older 0.42x
mutar I matched it against, but then, what can you expect for $20-ish from
dealer closeouts? ;-)


I think actual lenses could still be better choice, except for simple close
up adapters. The various Polaroid close up adapters actually do a fairly good
job for portrait work.



oh well, the search for the perfect camera, as with the perfect
cheeseburger, continues...


I don't think there is a perfect camera, though I find the old 6x9 folders
really intriguing. It is my hope to find an economical way to improve the
image quality, without getting too bulky, nor too complex, and still keeping
it fairly economical. I think money should be spent mostly on a good lens, or
two, probably something large format. The other solutions of focusing and
parallax might be solved with simple add-on rangefinders and a viewing finder
replacing the original window finder. The basic idea is a low cost ALPA 12
competitor, but with a more normal to short telephoto lens set-up, rather
than the wide bias of the ALPA. My guess is under $400 for all parts, sourced
from used gear, with the lens being the highest cost.

Ciao!

Gordon Moat
A G Studio
http://www.allgstudio.com

  #55  
Old May 14th 04, 07:31 PM
Q.G. de Bakker
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Default Omega 120 surprise convertible lens RF? Focal vs. leaf

Gordon Moat wrote:

I really wonder about the longer focal length, or telephoto usage. While

many
seem to want longer lenses, I question how much they actually get used.
[...]

Many medium format (645 or 6x6 mostly) photographers will claim using a

150
mm lens often. When looking at what these are most useful for, it is often
tight framing for portraits, either head shots, or only head and shoulders
(upper torso) images. While a longer lens can be less obtrusive to your
subject, by allowing more distance, I really wonder about the desire to
always fill the frame.


It's not about being less obtrusive.

Long lenses have a far wider use than just filling a frame with a tight head
shot. Are not restricted to portrait photography.
Landscape photography, for instance, wants a rather wide lens, or a long
one; you either show the lay of the land, or details. Or produce boredom.

And that (excluding the boring bits) is what makes short tele's very useful.
I think you're assumption ("what these are most useful for [etc.]") is
severely flawed.

With 6x6 photographers especially, most of the square
images get cropped anyway, so what is the big deal about cropping further.


What do you mean, "most of the square images get cropped anyway"?

The big deal about cropping is that you don't invest in MF equipment to end
up using bits of film no larger than the 35 mm miniature format.
And it's not the money, its why you spend the money: there is quality in
square mm/inches. The more the better.



  #56  
Old May 14th 04, 09:09 PM
Jim-Ed Browne
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Default Focal plane vs. leaf shutters in MF SLRs

The actual Polaroid Wink-Light hardware has only cheapness to
recommend it-it's the concept. A 12V car interior bulb, a switchmode
supply for a LCD backlight, a bridge rectifier, and the switching with
current and voltage in the safe limit for modern cameras could be used
to build a much more powerful device.

LED's are also a possibility. Build one and see!
  #57  
Old May 15th 04, 05:00 AM
Bob Monaghan
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Default Omega 120 surprise convertible lens RF? Focal vs. leaf


Hi Gordon, some very interesting comments, thanks ;-)

Polaroid 600SE

Yes, I should be more up on the Polaroid 600SE (See my notes and postings
http://medfmt.8k.com/mf/mamiyauniv.html but I went with Koni-Omega rather
than Mamiya Universal or Polaroid 600SE; if the mamiya univ. lenses
matched it would be more interesting as the 600SE is lighter (plastic).
IIRC, you needed to use some Mamiya Univ. M adapter plus parts from the
Polaroid 600SE back(s) to get roll film back operation rather than the
original fixed polaroid 100 film option (or send to Four Designs Corp. for
modification?).

So the stock polaroid 600se is very uninteresting unless you want to shoot
polaroids ;-) (perhaps cheap in these days of polaroid bankruptcy?) while
the modified versions still limit you to just the original polaroid lens
set rather than the full mamiya univ. series, and the 75mm is hard to find
etc. while the 127 and 150mm are rather close in focal length IMHO (versus
the Koni-Omega lineup of 58mm, 90mm, 135mm, and 180mm lenses, also made by
mamiya in some cases).

150mm lens

it isn't just the close focusing issue, which I agree with you can be
achieved by cropping. It is also that 150mm on MF 6x6cm equates to
90-105mm on 35mm SLR, which achieves the classic portraiture perspective;
using a wider lens can work with care, but the "big nose" effect is more
of a problem than with the short telephotos. It isn't just getting closer
to your subject jitters that makes the 150mm the classic MF portrait lens
;-)

I haven't had the $$ either to use/buy the Century Precision adapters for
movie work. The high cost of good examples like the Zeiss Mutars were what
led me to suggest that interchangeable lens front elements could be used
with very good results, sort of like interchanging filters, but with
thicker elements for the wide and telephoto variants. As we noted, this
was done in the past with Kodak Retina and Contaflex, and with modern
designs should be do-able again today ;-)

the final reason why this hasn't been done is that too many folks are
happy with the existing offerings, esp. of low cost folders (ikonta/moskva
clones..) or rangefinders such as Mamiya 7/6 and bronica rf645. I also
think the bronica RF should have done better, and if they had opted to
tweak the bodies to match the 135mm lenses, it would have been sold as a
plus factor rather than the recall approach they took, leaving us without
a longer lens than 100mm ;-( Cropping from 6x7 and 6x9cm is pretty
forgiving, as you noted, so that can cover some of the tasks.

So I should probably look for a better afocal telephoto adapter of 3X or
4X range for those admittedly infrequent shots (in which these telephoto
adapters incorporate a focusing setup, so what you see in focus thru the
adapter is what you get on the film ;-)

grins bobm
--
************************************************** *********************
* Robert Monaghan POB 752182 Southern Methodist Univ. Dallas Tx 75275 *
********************Standard Disclaimers Apply*************************
  #58  
Old May 15th 04, 05:16 AM
Bob Monaghan
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Default Focal plane vs. leaf shutters in MF SLRs


probably not. After all, a 12v car interior light is only so bright when
on continuously, and has to be heated to high temp to give off much light,
so "strobing" them on/off wouldn't do much for either brightness or
longevity. The LEDs can be strobed on/off fast, and get some benefits from
peak vs. average power dissipation issues, but again, LEDs are pricey and
don't put out all that much light either.

My typical homebrew underwater photo strobe tube uses a 200 watt-second
energy equiv. light pulse (in a microsecond); to equal it in brightness,
you would need to dump the equiv. of 200 watts for one second thru
whatever bulb or LED you want to use. And those multiple flashes would
have to add up to 200 watt-seconds even if the actual open shutter time is
1/250th second etc., so actual equivalent continuous power dissipation
would be enormous ;-)

But there aren't any 200 watt 12 volt car interior night lights, let alone
200 watt dissipation LEDs for low cost, and a hundred LEDs add up in cost
fast ;-) So we can be pretty sure that these LED cellphone lights are
going to be for sensitive detectors (1 candela?) and not for far distances
or very frequent use (unless you have a car battery in your backpack ;-)

That's why strobe tubes are still used in the 35mm repeated flash strobes,
but for much less peak power ;-( The cost of tubes that can sustain high
power flashes repeated in a short period of time is very high, and the
power supplies aren't portable either ;-)

grins bobm
--
************************************************** *********************
* Robert Monaghan POB 752182 Southern Methodist Univ. Dallas Tx 75275 *
********************Standard Disclaimers Apply*************************
  #59  
Old May 15th 04, 07:28 PM
Lassi Hippeläinen
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Default Focal plane vs. leaf shutters in MF SLRs

Bob Monaghan wrote:
...
But there aren't any 200 watt 12 volt car interior night lights, let alone
200 watt dissipation LEDs for low cost, and a hundred LEDs add up in cost
fast ;-) So we can be pretty sure that these LED cellphone lights are
going to be for sensitive detectors (1 candela?) and not for far distances
or very frequent use (unless you have a car battery in your backpack ;-)


The camera phones aren't very sensitive. You gotta keep the cost down...

Using LEDs is a must, because there is no room for a proper flash. The
latest LEDs are actully pretty effective. Their main problem is the
(in)stability of their colour over their life time. But still, they are
meant to be used as fill flash only - just as the Wink-Lite.

-- Lassi
  #60  
Old May 16th 04, 04:08 AM
Gordon Moat
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Default Omega 120 surprise convertible lens RF? Focal vs. leaf

"Q.G. de Bakker" wrote:

Gordon Moat wrote:

I really wonder about the longer focal length, or telephoto usage. While

many
seem to want longer lenses, I question how much they actually get used.
[...]

Many medium format (645 or 6x6 mostly) photographers will claim using a

150
mm lens often. When looking at what these are most useful for, it is often
tight framing for portraits, either head shots, or only head and shoulders
(upper torso) images. While a longer lens can be less obtrusive to your
subject, by allowing more distance, I really wonder about the desire to
always fill the frame.


It's not about being less obtrusive.

Long lenses have a far wider use than just filling a frame with a tight head
shot. Are not restricted to portrait photography.
Landscape photography, for instance, wants a rather wide lens, or a long
one; you either show the lay of the land, or details. Or produce boredom.

And that (excluding the boring bits) is what makes short tele's very useful.
I think you're assumption ("what these are most useful for [etc.]") is
severely flawed.


Fair enough. I suppose it was very over-generalized. Just to make it clear, I
have used long tele lenses for landscape and other non-portrait uses. I should
have typed a better response.



With 6x6 photographers especially, most of the square
images get cropped anyway, so what is the big deal about cropping further.


What do you mean, "most of the square images get cropped anyway"?


Usage patterns, in that there are not many square images that get printed, at
least in publications. Of course, there are some that only do square image
prints, so again this is over-generalized. i don't think it is possible to
state anything on this news group without someone refuting it, however, at some
point assumptions need to be made for point of argument, or just to try to make
a point.

I feel that I have not stated this well enough. Let's try: . . . with the
larger than 35 mm film area, and great modern emulsions, cropping is one great
creative tool. Using that tool of cropping ability, one can accomplish
particular desired framing or coverage in the final printed image by cropping.
Obviously, if one only accepts the absolute maximum extent of quality in a
system, then cropping could be an unacceptable option. I don't have any
problems cropping an image, so I choose to use cropping as a creative choice.





The big deal about cropping is that you don't invest in MF equipment to end
up using bits of film no larger than the 35 mm miniature format.
And it's not the money, its why you spend the money: there is quality in
square mm/inches. The more the better.


Obviously, but I am not against cropping a few millimetres to get a different
end composition. There is a group of photographers that do not believe in using
cropping, but I am not one of them. Also, I have never cropped any medium
format film down to 35 mm size, nor even close to it. In fact, it is tough to
use much of any cropping with 35 mm film, so framing tends to be much more
exacting requirements to maintain the more limited quality, not that I am
advocating sloppy framing for medium format.

Ciao!

Gordon Moat
A G Studio
http://www.allgstudio.com

 




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