Huge Telephoto (900mm f/3.2 and Pentax 6X7)

K David · 05-19-2017, 11:04 AM - **1 Like**

That's a Pentax 6X7 on the back of that lens. Here's a link to the article: 900mm Govt. surplus lenses have their uses ...

The lens in that photo was a home-made 900mm f/3.2 lens made from surplus military optics. Whether it can make full use of that f/3.2 speed is unknown given the clear aperture of the 6X7 mount; so in practical application it might be somewhat slower than f/3.2 in use. The article is an interesting read about home-made lenses and the sample photos are worth checking out. It would have been good if they'd shared some 4X5 images with it, too. I've made some home-made lenses (much smaller) before and had great results.

photolady95 · 05-19-2017, 12:16 PM

Moved to correct forum as the Sticky in General Talk says, no photography talk here.

itshimitis · 05-19-2017, 12:39 PM

Wow - that looks handholdable lol. Where's my back pack?

05-19-2017, 11:04 AM - 1 Like	#1
K David Veteran Member Join Date: Oct 2012 Location: Colorado Photos: Gallery Posts: 1,437	Huge Telephoto (900mm f/3.2 and Pentax 6X7) That's a Pentax 6X7 on the back of that lens. Here's a link to the article: 900mm Govt. surplus lenses have their uses ... The lens in that photo was a home-made 900mm f/3.2 lens made from surplus military optics. Whether it can make full use of that f/3.2 speed is unknown given the clear aperture of the 6X7 mount; so in practical application it might be somewhat slower than f/3.2 in use. The article is an interesting read about home-made lenses and the sample photos are worth checking out. It would have been good if they'd shared some 4X5 images with it, too. I've made some home-made lenses (much smaller) before and had great results.

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05-19-2017, 12:16 PM	#2
photolady95 Otis Memorial Pentaxian Join Date: May 2009 Location: Cruising the forum watching his back Photos: Gallery \| Albums Posts: 12,712	Moved to correct forum as the Sticky in General Talk says, no photography talk here.

05-19-2017, 12:39 PM	#3
itshimitis Pentaxian Join Date: May 2011 Location: All over the place Posts: 3,535	Wow - that looks handholdable lol. Where's my back pack?