What's limiting P&S f/stop?

NikolaiNikolai Registered Users Posts: 19,035 Major grins
edited May 10, 2007 in Cameras
Most P&S cameras I'm aware of have the highest f/number around f/8, maaaybe f/11. Is it because of the overall smaller lense diameter? But pin-hole cameras prove that you can have a really tiny hole and still get the picture. What gives? :scratch
"May the f/stop be with you!"

Comments

  • David_S85David_S85 Administrators Posts: 13,245 moderator
    edited May 7, 2007
    Nikolai wrote:
    Most P&S cameras I'm aware of have the highest f/number around f/8, maaaybe f/11. Is it because of the overall smaller lense diameter? But pin-hole cameras prove that you can have a really tiny hole and still get the picture. What gives? headscratch.gif

    At sub-miniature sensor (1/1/8, 1/2.5" & the like) sizes and teensy weensy lenses, f/8 and f/11 are already at logical diffraction limits. F 16 would be a fraction of a millimeter, and become useless optically.
    My Smugmug
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  • NikolaiNikolai Registered Users Posts: 19,035 Major grins
    edited May 7, 2007
    David_S85 wrote:
    At sub-miniature sensor (1/1/8, 1/2.5" & the like) sizes and teensy weensy lenses, f/8 and f/11 are already at logical diffraction limits. F 16 would be a fraction of a millimeter, and become useless optically.

    David, thanks!

    So, you confirm my assumption that it's the sheer diameter of the optical path?
    I understand that about the subcompacts and camera phones, but I thought that sub-$1000 P&S (like my late sony F828) have decent size high quality glass and even sensor on par with many entry level dslrs. headscratch.gif
    "May the f/stop be with you!"
  • gusgus Registered Users Posts: 16,209 Major grins
    edited May 7, 2007
    Nikolai wrote:
    Most P&S cameras I'm aware of have the highest f/number around f/8, maaaybe f/11. Is it because of the overall smaller lense diameter? But pin-hole cameras prove that you can have a really tiny hole and still get the picture. What gives? headscratch.gif
    I'll also take a stab nik. My pin hole cameras use about the f/350-400 range thus we are looking at about .3mm hole at 100-125mm length (yeah i snap a lot of drill bits at $2 each)

    Imagine getting a $300 camera to be able to mechanically close to that size with accuracy. This info is all totally irrelevant to your question though but i wanted to sound like i knew something.
  • David_S85David_S85 Administrators Posts: 13,245 moderator
    edited May 7, 2007
    All the same, I wish dSLR's and L-lenses could be successfully miniaturized to 1/5th their actual size and still deliver similar results. Would be much easier getting them into concerts and pockets.
    My Smugmug
    "You miss 100% of the shots you don't take" - Wayne Gretzky
  • NikolaiNikolai Registered Users Posts: 19,035 Major grins
    edited May 7, 2007
    Thanks Gus and David!
    "May the f/stop be with you!"
  • claudermilkclaudermilk Registered Users Posts: 2,756 Major grins
    edited May 7, 2007
    gus wrote:
    I'll also take a stab nik. My pin hole cameras use about the f/350-400 range thus we are looking at about .3mm hole at 100-125mm length (yeah i snap a lot of drill bits at $2 each)

    Imagine getting a $300 camera to be able to mechanically close to that size with accuracy. This info is all totally irrelevant to your question though but i wanted to sound like i knew something.

    Sounds reasonable to me. We are talking tiny movements on these things.

    BTW, ever thought about a drill press? They even have rigs for the Dremel tools.
    Chris
    http://www.chrislaudermilkphoto.com/
  • gusgus Registered Users Posts: 16,209 Major grins
    edited May 7, 2007
    claudermilk wrote:
    Sounds reasonable to me. We are talking tiny movements on these things.

    BTW, ever thought about a drill press? They even have rigs for the Dremel tools.
    I use a dremel but by hand. Its all over in a fraction of a second. The real trick is to keep that tiny hole clean of rough edges & then blacking it out around the inside of the hole to stop reflection. I drill into brass shim sheets.
  • TanukiTanuki Registered Users Posts: 184 Major grins
    edited May 8, 2007
    Nikolai wrote:
    Most P&S cameras I'm aware of have the highest f/number around f/8, maaaybe f/11. Is it because of the overall smaller lense diameter? But pin-hole cameras prove that you can have a really tiny hole and still get the picture. What gives? headscratch.gif

    David_S85 has a good point about diffraction being potentially the limiting factor, but I'm curious why you want smaller aperatures than f/8. Consider the following:

    1. The lenses on P&S cameras are very wide angle lenses compared to 35mm camera lenses. With such a wide angle lens, you get much more depth of field than with an 35mm equivalent focal length lens.

    2. Small aperatures tend to require higher ISOs. Considering that P&S sensors are only good at ISO 100 and slower, your opportunities to use f/16 and beyond are limited.

    Even if diffraction were not an issue, these two other considerations might make it unnecessary for camera manufacturers to provide smaller aperatures than f/8 or f/11.

    Just my 2 cents, anyway.

    Mike
  • claudermilkclaudermilk Registered Users Posts: 2,756 Major grins
    edited May 8, 2007
    gus wrote:
    I use a dremel but by hand. Its all over in a fraction of a second. The real trick is to keep that tiny hole clean of rough edges & then blacking it out around the inside of the hole to stop reflection. I drill into brass shim sheets.

    http://www.shop.com/op/~Dremel_Drill_Press-prod-40618002-54028282?sourceid=298
    thumb.gifdeal.gif

    So, any examples of these pinhole projects? Sounds cool.

    BTW, sorry for the hijack....
    Chris
    http://www.chrislaudermilkphoto.com/
  • NikolaiNikolai Registered Users Posts: 19,035 Major grins
    edited May 8, 2007
    Tanuki wrote:
    ...I'm curious why you want smaller aperatures than f/8...
    1. Long exposures
    2. Deep DOF
    3. Sun-shooting
    "May the f/stop be with you!"
  • TanukiTanuki Registered Users Posts: 184 Major grins
    edited May 9, 2007
    Nikolai wrote:
    1. Long exposures
    2. Deep DOF
    3. Sun-shooting

    I just stumbled upon this very well-written tutorial at Cambridge in Color. Well worth the read. It has some handy calculators to compare depth of field for different sensor sizes. You could use this to quantify what depth of field you are or aren't missing if your P&S can only go to f/8. I think what you'll find is that you're really missing with a P&S is the option for shallow depth of field. Small sensors just can't make it happen.

    For long exposures, you could always use a ND filter if the P&S accepts standard filters.

    Not sure what you mean by sun-shooting. headscratch.gif Sounds kind of dangerous.

    Mike
  • NikolaiNikolai Registered Users Posts: 19,035 Major grins
    edited May 9, 2007
    Mike,
    Tanuki wrote:
    Not sure what you mean by sun-shooting. headscratch.gif Sounds kind of dangerous.
    Mike
    Something like this:
    76033817-L.jpg

    You can't really get a decent "star" out of 35mm-type lens unless you close down about f/20.
    "May the f/stop be with you!"
  • TanukiTanuki Registered Users Posts: 184 Major grins
    edited May 10, 2007
    Nikolai wrote:
    Something like this:

    You can't really get a decent "star" out of 35mm-type lens unless you close down about f/20.

    Wow! That's an amazing shot. Was it with film or digital?
  • tsk1979tsk1979 Registered Users Posts: 937 Major grins
    edited May 10, 2007
    How did you cover that much dynamic range!!?
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  • NikolaiNikolai Registered Users Posts: 19,035 Major grins
    edited May 10, 2007
    Tanuki wrote:
    Wow! That's an amazing shot. Was it with film or digital?
    Thanks:-) :D
    All digital, baby mwink.gif , I stopped doing film thingie almost 10 years ago:-) deal.gif
    "May the f/stop be with you!"
  • NikolaiNikolai Registered Users Posts: 19,035 Major grins
    edited May 10, 2007
    tsk1979 wrote:
    How did you cover that much dynamic range!!?

    RAW + post-processing. Modern cameras and sowftware are quite capable if you use them right:-)
    "May the f/stop be with you!"
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