how does this happen?

amadeusamadeus Major grinsPosts: 2,100Registered Users Major grins

today I'm out shooting and I see this hawk on top of a tree. I stop the car and get out and he then flies off to another tree but now I'm facing dead into the sun. I was using my nikon D4 with the 300 f.8 prime with a nikon 1.7 tc.

shooting shutter priority with a fast shutter 3200 and ISO 2500. not the best settings but I had just been shooting another hawk in a much darker setting.

I was just curious how the shot would look right into a very low strong sun. when I shot it and looked at it I noted F stop was F 36.

I didn't think this camera or lens would even go to F36?

How does this happen?

https://photos.smugmug.com/Motorcycles/2017/i-mdsHCXQ/0/X2/102-X2.jpg

Comments

  • RichardRichard Mildly bemused Madrid, SpainPosts: 18,777Administrators, Vanilla Admin moderator

    Moved to technique.

    Seems like the camera did just what you told it to. At those ISO and shutter settings (which were fixed), it had to use a very small aperture to avoid over-exposing. I don't know anything about the specs of the camera or lens, but there's an old philosophical principle that says, that which exists is possible :smiley:

  • ziggy53ziggy53 Still learnin'still lovin Posts: 20,724Super Moderators moderator
    edited January 22, 2017

    @amadeus said:
    today I'm out shooting and I see this hawk on top of a tree. I stop the car and get out and he then flies off to another tree but now I'm facing dead into the sun. I was using my nikon D4 with the 300 f.8 prime with a nikon 1.7 tc.

    shooting shutter priority with a fast shutter 3200 and ISO 2500. not the best settings but I had just been shooting another hawk in a much darker setting.

    I was just curious how the shot would look right into a very low strong sun. when I shot it and looked at it I noted F stop was F 36.

    I didn't think this camera or lens would even go to F36?

    How does this happen?

    https://photos.smugmug.com/Motorcycles/2017/i-mdsHCXQ/0/X2/102-X2.jpg

    Your AF-S NIKKOR 300mm F2.8G ED VR (or AF-S NIKKOR 300mm F2.8G ED VR II) has physical apertures of f2.8-f22.

    All optical teleconverter assemblies induce some light loss and the TC-17E II has a rated loss factor of 1.5 stops.

    f22 plus 1.5 stops = f36, so your physical aperture was an f22, with an effective aperture of f36 using the 1.7x teleconverter.


    Sadly, all teleconverters also induce a resolution loss and the TC-17E II is no different. Nasim Mansurov rates the resolution loss at: "Nikon TC-17E II – 17% Sharpness Loss".

    For his article: "Image Degradation with Nikon Teleconverters"

    ziggy53
    Moderator of the Cameras and Accessories forums
  • amadeusamadeus Major grins Posts: 2,100Registered Users Major grins

    %17!!!! wow I didn't know that much. thanks for the response and info.

  • petrochemistpetrochemist Essex UKPosts: 10Registered Users Big grins
    FWIW, I gather most cameras don't tell you the effective aperture taking into account TCs or extension tubes. I've only ever heard of Nikon doing this.
  • ziggy53ziggy53 Still learnin'still lovin Posts: 20,724Super Moderators moderator

    @petrochemist said:
    FWIW, I gather most cameras don't tell you the effective aperture taking into account TCs or extension tubes. I've only ever heard of Nikon doing this.

    Canon teleconverters also pass the aperture information back to the body with a correction factor so that the Canon body does properly calculate the effective aperture, and it stores this effective aperture in the EXIF, same as Nikon.

    The problem occurs with third-party extenders which may lack all the pins necessary to relay the correction information to the body. (Although some of the third-party extenders "do" have the necessary pins, so you just have to be aware when you purchase.)

    Alternately, some folks intentionally "tape" the extra pin on Canon extenders to mask the extender correction from the body. The reason to do this is so that the camera body continues to allow autofocus even with a physical aperture setting of f8 (or f5.6 on lesser bodies). Otherwise, with the correction pin allowed to contact the camera reverts to manual focus with focus confirmation when it senses an "effective" aperture of f8 (or f5.6 on lesser bodies).

    ziggy53
    Moderator of the Cameras and Accessories forums
  • pathfinderpathfinder Drive By Digital Shooter western IndianaPosts: 14,383Super Moderators moderator

    There's no free lunch - you want a longer focal length, at the same aperture diameter ( the front optic didn't get bigger with your TC ) , the f stop gets larger, the optical aperture is smaller. I know that Canon and Nikon are quite up front about this effect. 1.4 TC's cost one stop of light, and a 2X TC costs two stops of aperture. Nikon's 1.7 TC costs ~1.5 stops.

    I know that my Canon TC's transfer the aperture date to my camera's exif files with the "corrected" aperture size with the TC in place. My 300 f2.8 becomes a 420mm f4 optic. My 500 f4 becomes a 700mm f5.6 with a 1.4TC.

    That's why you can only use a 2X TC with f2.8 lenses usually. F4 primes drop to f8 with a 2X TC, and many camera bodies no longer AF with f8 lenses. The viewfinder also gets pretty dim as well in anything but bright sunlight.

    Like I said, no free lunch.

    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • petrochemistpetrochemist Essex UKPosts: 10Registered Users Big grins

    @ziggy53 said:

    Canon teleconverters also pass the aperture information back to the body with a correction factor so that the Canon body does properly calculate the effective aperture, and it stores this effective aperture in the EXIF, same as Nikon.

    The problem occurs with third-party extenders which may lack all the pins necessary to relay the correction information to the body. (Although some of the third-party extenders "do" have the necessary pins, so you just have to be aware when you purchase.)

    Alternately, some folks intentionally "tape" the extra pin on Canon extenders to mask the extender correction from the body. The reason to do this is so that the camera body continues to allow autofocus even with a physical aperture setting of f8 (or f5.6 on lesser bodies). Otherwise, with the correction pin allowed to contact the camera reverts to manual focus with focus confirmation when it senses an "effective" aperture of f8 (or f5.6 on lesser bodies).

    It seems was wrong with teleconverters then (most cameras these days would be either Nikon or Canon). The web discussion I was remembering may have been about extension tubes - do Canon correct EXIF aperture for extension?
    AFAIK none of my TCs or extension tubes alter electronic details at all (unless they don't pass them through at all!).

    I must admit I'd be rather annoyed if my camera refused to try AF due to aperture, yet proved to be quite capable of managing if that signal's blocked. A viewfinder warning light would seem a better approach if it's outside the realm of reliability.

  • ziggy53ziggy53 Still learnin'still lovin Posts: 20,724Super Moderators moderator

    @petrochemist said:

    I must admit I'd be rather annoyed if my camera refused to try AF due to aperture, yet proved to be quite capable of managing if that signal's blocked. A viewfinder warning light would seem a better approach if it's outside the realm of reliability.

    AF reliability is definitely affected at smaller apertures, both for focus accuracy and for focus acquisition. Taping the telextender pins to retain AF will reduce the keeper rate, but many view this as an acceptable compromise and just increase their rate of capture to help compensate.

    A Teleconverter/Telextender should always be considered either a convenience or an act of desperation. The result is almost never as good as an actual prime, or modern, high-quality zoom, of the same/equivalent focal length. (Although a telextender is often better than cropping with interpolation in postproduction.)

    @petrochemist said:

    It seems was wrong with teleconverters then (most cameras these days would be either Nikon or Canon). The web discussion I was remembering may have been about extension tubes - do Canon correct EXIF aperture for extension?
    AFAIK none of my TCs or extension tubes alter electronic details at all (unless they don't pass them through at all!).

    A discussion of extension tubes is tangential to what the original poster inquired. Click here to go to a new thread for that discussion.

    ziggy53
    Moderator of the Cameras and Accessories forums
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