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Minolta RF 800mm 1:8 converted to EOS...
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PostPosted: Mon Oct 25, 2010 7:10 pm    Post subject: Minolta RF 800mm 1:8 converted to EOS... Reply with quote
For starters, these are the only two posts on the WWW that has information about this lens:

http://www.minolta-forum.de/forum/4homepages/details.php?image_id=7054

http://www.flickr.com/photos/kenwales/4277800414/

So here’s an unusual find, at least for me. The Minolta RF 800mm 1:8 Catadioptric. When I acquired this lens last month I immediately began work on an EOS mount. Knowing that it had zero aperture mechanics I was sure it was going to be an easy conversion. The only question I had in the beginning was whether or not the screw-in filter (screws into the Minolta RS mount) was required or not. Well after some searching I came across a good review of the Minolta 500mm f/8 RF Rokkor-X and in this review Antony does point out that the screw-in filter should stay in for performance. So know this set me back a little, but I got it figured out.

#1 The package:


#2 The guts:


#3 The mounts. On the left is a machined M42-EOS adapter with an epoxied 42-to-39mm reducing bushing which, to my astonishment, works as a perfect mate to the screw-in 39mm filter.


#4 The EOS conversion complete (non-destructive, i.e. this is fully reversible back to stock). The ONLY removal of Minolta stock I had to do was 1mm of the Minolta normal screw-in filter housing. Also shown is a hand-crafted aluminum filter key:


#5 Here’s the lens along with the Canon EF 17-40mm f/4L USM for comparison:


#6 LOL, give a photog a mm and he’ll want a few more Smile The 7-element RMC Tokina Doubler converted to EOS:


#7 2560mm f/16 Effective Smile


SAMPLES

This moon shot was taken from downtown Austin, TX by Greg Daem with a Canon EOS 50D:


The moon at 1600mm including a video.

All the rest of the sample shots

Thanks for looking,
Roy


PostPosted: Mon Oct 25, 2010 7:15 pm    Post subject: Reply with quote
Holy cow what a beast! Shocked Shocked

What is the weight?

Nice moon shot btw Smile


PostPosted: Mon Oct 25, 2010 10:07 pm    Post subject: Reply with quote
Nice clean job. Would like to see more images from it.


PostPosted: Mon Oct 25, 2010 10:28 pm    Post subject: Reply with quote
Really nice documentation, Roy. Maybe next time I'm up Austin way, I can drop by and feast my eyes on that puppy, eh?

Looking at your photos over at flickr, I was impressed by the sharpness even at 2560mm with the 2x. Seems to be an exceptional lens. Look forward to seeing more pics from this light bucket.


PostPosted: Tue Oct 26, 2010 2:33 am    Post subject: Reply with quote
Roy, that's a real beauty.
I'm in awe.


PostPosted: Tue Oct 26, 2010 2:33 am    Post subject: Reply with quote
I hope you have a sturdy ( read, very sturdy) tripod.


PostPosted: Tue Oct 26, 2010 5:34 am    Post subject: Reply with quote
This is really cool! That's a great looking lens and what's even better is your results look quite impressive. The full moon shot on flickr looks soft though (unlike the other moon shots). Was there some other variable at play here? Judging by your waxing/waning shots, it appears this lens can yield some very sharp images.

Great job giving that beauty some new life!


PostPosted: Tue Oct 26, 2010 1:12 pm    Post subject: Reply with quote
Thanks everyone for the comments. Michael, all the moon shots were waxing towards full. The conditions were not ideal...low elevation, partly cloudy, and low pressure. The 99% full moon shot was taken with the 2X TC and it does take a hit on IQ. Personally for the moon the best situation would be to use it native at 800mm on a crop sensor body with the best conditions.


PostPosted: Sat Oct 30, 2010 10:17 am    Post subject: Reply with quote
This lens looks incredible, pictures are very good !


PostPosted: Sat Oct 30, 2010 6:04 pm    Post subject: Reply with quote
motleypixel wrote:
The 99% full moon shot was taken with the 2X TC and it does take a hit on IQ. Personally for the moon the best situation would be to use it native at 800mm on a crop sensor body with the best conditions.


I agree with this. I've found that, when using my 500mm and 650mm telephotos to photograph the moon, there is no advantage to using a 2x -- and I have a good 2x. No additional detail is visible, and there is a very small level of image degradation evident. Slight enough that I would call it negligible. About the only advantage to using a 2x is the cropped image is twice as big, which can be useful for a final print.

You probably know this already, but I've found that the best position for the moon when taking photos of it -- unfortunately -- is when it is directly overhead. I say "unfortunately" because it really kills my back to shoot photos in this position. I don't have an angle finder yet and even if I did, I would still need to use Live View and my camera does not have an articulated LCD screen. Overhead is always best because there's less atmosphere to shoot through. Taking shots of the moon shortly after moon rise can be quite dramatic also, especially if there's a lot of dust or other particulates in the atmosphere. Recently I grabbed some shots at moon rise where it was a vivid red color. Difficult to do, though. The moon is not nearly as bright when it first peeks over the horizon as it is when it is overhead. And in order to produce that striking red color, the level of atmospheric haze was such that the light was reduced even further. I had to bump up the ISO to 800 and shoot with my lens wide open, otherwise I would have had motion-induced blur -- motion of the moon, that is.


PostPosted: Sat Oct 30, 2010 6:28 pm    Post subject: Reply with quote
[quote="cooltouch"]
motleypixel wrote:

.... otherwise I would have had motion-induced blur -- motion of the moon, that is.


I'm a little bit surprised reading this Michael.
That means you use a slow shutter.
Or, in my experience, I use 1/20 to 1/40 shutter speed.


PostPosted: Sat Oct 30, 2010 10:33 pm    Post subject: Reply with quote
[quote="Himself"]
cooltouch wrote:
motleypixel wrote:

.... otherwise I would have had motion-induced blur -- motion of the moon, that is.


I'm a little bit surprised reading this Michael.
That means you use a slow shutter.
Or, in my experience, I use 1/20 to 1/40 shutter speed.


Well, when the moon is well up in the sky, correct exposure at ISO 100 is 1/125 @ f/8 or f/11 (I prefer f/11, although f/8 works fine). But when the moon is just barely above the horizon, and with the atmospheric conditions that were causing the moon to turn red, it was just very dim. At ISO 100, I was getting exposures of 1/4 to 1/2 second, which is slow enough to cause motion blur with a long telephoto. By bumping up the camera's ISO to 800, and opening the lens up a stop, I was able to get the shutter speed up to a fast enough speed, 1/60 I think.


PostPosted: Tue Mar 01, 2011 3:12 am    Post subject: Reply with quote
So Antony North (The Rokkor Files) has released a review of my lens...since it's rare he obliged to review it: Minolta RF 800mm 1:8 review on The Rokkor Files


PostPosted: Tue Mar 01, 2011 4:35 am    Post subject: Reply with quote
Interesting read!
I saw the post today on FM and read it from there.


PostPosted: Sun Jun 05, 2011 10:40 am    Post subject: Reply with quote
Sorry to dig this up again but for anyone interested there is another for sale on uk ebay http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=200614999532&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en#ht_734wt_1141


PostPosted: Sun Jun 05, 2011 12:21 pm    Post subject: Reply with quote
Roy, that is a very impressive lens. I have recently discovered the joy of using mirror lenses but not on a tripod.
Have a read of my post & hopefully it may help you get the most out of that beauty.

http://forum.mflenses.com/reflex-nikkor-500mm-a-different-point-of-view-t39527.html


PostPosted: Sun Jun 05, 2011 4:20 pm    Post subject: Reply with quote
Hey, thanks for resurrecting the thread! Somehow I managed to miss motleypixel's post about the Rokkor Files review. It was well worth the read.


PostPosted: Mon Jun 06, 2011 8:42 pm    Post subject: Reply with quote
AussieBob wrote:
Roy, that is a very impressive lens. I have recently discovered the joy of using mirror lenses but not on a tripod.
Have a read of my post & hopefully it may help you get the most out of that beauty.

http://forum.mflenses.com/reflex-nikkor-500mm-a-different-point-of-view-t39527.html

Thx for the tip (i.e. better shock absorber than a tripod).
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