DennisS
Posts: 1292
Location: Los Anglels, United States
Registered: 1 Sep 2007
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Lightweight/compact rig for hiking and cycling
Posted: 2 Oct 2011 at 22:42 GMT
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I have finally had time to play around with my NEX-5/Samyang 7.5 lens combo. Spent most of the day Saturday in my garage. Here is the result:
Sure wish I had access to a CNC mill.
There is 5 degrees of tilt in the part between the monopod and what is left of my NN R1 pano head. The monopod is a Gitzo. The entire rig weighs 2lbs 1oz. I am still trying to figure out the NPP and optimum lens settings that give the sharpest results.
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DemonDuck
Posts: 312
Location:
Registered: 10 Mar 2011
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Re: Lightweight/compact rig for hiking and cycling
Posted: 3 Oct 2011 at 2:12 GMT
updated: 3 Oct 2011 at 2:14 GMT
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I know it takes time to get used to new equipment. I'm anxious to see some pano's after you get to know your stuff.
Try some with the diagonal of the sensor vertical. I've always wondered how that would work.
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badders
Posts: 384
Location: East Kilbride, United Kingdom
Registered: 5 Dec 2007
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Re: Lightweight/compact rig for hiking and cycling
Posted: 3 Oct 2011 at 6:14 GMT
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DennisS said: I am still trying to figure out the NPP and optimum lens settings that give the sharpest results.
I found best results @ f/5.6 with the focus pulled just a tad back from infinity.
Andrew Baddeley
www.360tacticalvr.com
stores.ebay.co.uk/360tacticalvr
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Trausti - FFC
Posts: 57
Location:
Registered: 20 Aug 2011
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Re: Lightweight/compact rig for hiking and cycling
Posted: 3 Oct 2011 at 6:27 GMT
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Very nicely done!
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Smooth
Posts: 3774
Location: Mount Panorama, Australia
Registered: 21 Jul 2004
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Re: Lightweight/compact rig for hiking and cycling
Posted: 3 Oct 2011 at 7:17 GMT
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Neat job Dennis,
I see you have run with attaching the adapter the same way I went about it. I did a little more testing today and f/11.0 is still the best I have found for this combination. f/9.5 is softer on the edges but better than f/8.0 the issue as you know is slight diffraction in the centre with f/11.0. I do think I can get around this with a little shave to the rear mounting plate.
badders said: I found best results @ f/5.6 with the focus pulled just a tad back from infinity.
I guess you are basing this on a Micro 4/3rds camera body? No way that f/5.6 on the Sony NEX is best.
Regards, Smooth 
www.omnipix.com.au
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Smooth
Posts: 3774
Location: Mount Panorama, Australia
Registered: 21 Jul 2004
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Re: Lightweight/compact rig for hiking and cycling
Posted: 3 Oct 2011 at 7:43 GMT
updated: 3 Oct 2011 at 7:44 GMT
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Here are some test crops from the (Shaved) Samyang 7.5mm Fisheye on the Sony NEX.
Close Edge focus
Far/Infinity
As you can see there is no discernible difference in the infinity shots only slight lighting differences from my flicking television.
Regards, Smooth
www.omnipix.com.au
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badders
Posts: 384
Location: East Kilbride, United Kingdom
Registered: 5 Dec 2007
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DennisS
Posts: 1292
Location: Los Anglels, United States
Registered: 1 Sep 2007
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Re: Lightweight/compact rig for hiking and cycling
Posted: 3 Oct 2011 at 13:25 GMT
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I found best results @ f/5.6 with the focus pulled just a tad back from infinity. That would work with a 4/3 camera/lens combo that is designed to work together as a system.
The Samyang 7.5 was never designed to work on the NEX. In order to get the lens to focus at infinity, you have to take the lens apart and remove whatever spacers you find. Smooth had 3 brass in his, I had 1 brass and 1 very thin steel. The steel shim measured .0025" thick. The number of spacers you have in your lens will dictate your focus setting. I think this will be different for different people.
The focus is very touchy. A small adjustment makes a huge difference in your results.
With my Sigma 8mm lens, it was easy to find an f stop that gave good results all the way across the image. At F11 the edges of the Samyang are good, but there is visible diffraction in the center. At f8, the center looks good, but the edges are soft. Initial tests are not as promising as the Sigma 8mm. I have to spend more time testing before I start shooting any panos.
I used Smooth's method of bolting the adapter to the lens. I removed the very sharp spring steel piece and turned down the outside diameter to the same diameter as the lens mount. As a result, there was nothing keeping the adapter in place. Since the lens body is plastic, I will feel more comfortable with this mod after I locate longer screws.
Setting the crop circle in PTGui is another issue. This lens “sees” the shaved hood as it appears at the top and bottom of the image. It almost seems like the lens can see beyond the vertical plane. I do not know exactly where to set the crop circle. Do I set it to cover just the part of the image I want or to the entire image? If I do not use the entire image, what lens size do I enter?
Much more testing is required before I decide if I like this lens.
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Smooth
Posts: 3774
Location: Mount Panorama, Australia
Registered: 21 Jul 2004
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Re: Lightweight/compact rig for hiking and cycling
Posted: 3 Oct 2011 at 14:05 GMT
updated: 3 Oct 2011 at 14:07 GMT
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DennisS said: In order to get the lens to focus at infinity, you have to take the lens apart and remove whatever spacers you find. Smooth had 3 brass in his, I had 1 brass and 1 very thin steel. The steel shim measured .0025" thick. The number of spacers you have in your lens will dictate your focus setting. I think this will be different for different people.
I suggest you machine away the thickness of the combined spacers (or the thickness of the added adapter) from the rear (front edge) where the metal end cap touches the plastic body. This will make up for the lack of length of the screws and move the rear lens element closer to the sensor allowing for more (thus, better) focus adjustment around the infinity setting of the lens scale. I have a feeling the diffraction at f/11 is actually the lens not reaching true infinity focusing because the rotation ring is hitting it's limit. Again, shaving the end mounting cap will overcome this.
DennisS said: Setting the crop circle in PTGui is another issue. This lens “sees” the shaved hood as it appears at the top and bottom of the image. It almost seems like the lens can see beyond the vertical plane. I do not know exactly where to set the crop circle. Do I set it to cover just the part of the image I want or to the entire image? If I do not use the entire image, what lens size do I enter?
The crop circle should be set around the viewable scene image. In my screen shot you can see I have taken it to the very edge. This runs out at 4470x4470 but you could come inside the blue vignetting mark you can see at the bottom left of the panohead and this would reduce the crop circle to say 4460x4460.
When you are wanting to enter a starting lens parameter, 8mm works perfectly.
My stitched images with perfectly optimized control points shows this lens to be 7.69mm. This number can jump around a bit, but generally this is the norm.
Regards, Smooth
www.omnipix.com.au
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DennisS
Posts: 1292
Location: Los Anglels, United States
Registered: 1 Sep 2007
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Re: Lightweight/compact rig for hiking and cycling
Posted: 3 Oct 2011 at 15:56 GMT
updated: 3 Oct 2011 at 15:59 GMT
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Thanks Smooth.
Looks like you can still see some of the lens petal on the top left corner and the left edge of your picture. Since this area is well inside the overlap, I don't see a problem. I can also see in your image how the lens can still see the fully shaved hood at the top. Too dark at the bottom to see. I get the same thing.
Another problem I am having is keeping my hand out of the picture! Since the front of the lens is so very close to the camera grip, my hand keeps getting into the picture. The front of my Sigma lens was plenty far enough away as it was not a problem. I am thinking about flipping the camera 180 so the shutter trigger is below the lens, not above it. This would not solve the problem of keeping my hand out of the picture for the Nadir patch shot. Damn this camera/lens is small!
Dennis
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Smooth
Posts: 3774
Location: Mount Panorama, Australia
Registered: 21 Jul 2004
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Re: Lightweight/compact rig for hiking and cycling
Posted: 3 Oct 2011 at 16:24 GMT
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DennisS said: Looks like you can still see some of the lens petal on the top left corner and the left edge of your picture.
Yes, this was before I did my final file down. Didn't matter anyway!.DennisS said: I can also see in your image how the lens can still see the fully shaved hood at the top. Too dark at the bottom to see. I get the same thing.
I think you'll find this is the internal wall of the lens being illuminated. I've seen exactly the same thing with a Sigma 8mm and Nikon FC-E8/E9 or any circular fisheye really. You are noticing it more because this is like 192 degrees compared to 180 degrees of the Sigma (actually less on 1.6x). Nothing to worry about at all. You just have to position the crop circle.DennisS said: Another problem I am having is keeping my hand out of the picture! Since the front of the lens is so very close to the camera grip, my hand keeps getting into the picture. I am thinking about flipping the camera 180 so the shutter trigger is below the lens, not above it. This would not solve the problem of keeping my hand out of the picture for the Nadir patch shot.
I use a remote!
DennisS said: Damn this camera/lens is small!
So very true 
Regards, Smooth
www.omnipix.com.au
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DennisS
Posts: 1292
Location: Los Anglels, United States
Registered: 1 Sep 2007
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Re: Lightweight/compact rig for hiking and cycling
Posted: 3 Oct 2011 at 16:49 GMT
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Smooth said: I use a remote!
Kind of hard with a monopod.
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Jaime
Posts: 30
Location: Elche, Spain
Registered: 14 Sep 2011
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DennisS
Posts: 1292
Location: Los Anglels, United States
Registered: 1 Sep 2007
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Re: Lightweight/compact rig for hiking and cycling
Posted: 3 Oct 2011 at 16:59 GMT
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I suggest you machine away the thickness of the combined spacers (or the thickness of the added adapter) from the rear (front edge) where the metal end cap touches the plastic body. This will make up for the lack of length of the screws and move the rear lens element closer to the sensor allowing for more (thus, better) focus adjustment around the infinity setting of the lens scale. I have a feeling the diffraction at f/11 is actually the lens not reaching true infinity focusing because the rotation ring is hitting it's limit. Again, shaving the end mounting cap will overcome this.
I just finished removing .012" from the inside of the mounting flange. F11 is now in focus in the center and at the edges. F8 is still soft in the corners. If I take any more off, I will not be able to focus at infinity with the focusing ring turned all the way to the stop.
A series of panoramas will now tell me the quality. With this latest mod, images look as good as the Sigma 8mm.
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Smooth
Posts: 3774
Location: Mount Panorama, Australia
Registered: 21 Jul 2004
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Re: Lightweight/compact rig for hiking and cycling
Posted: 3 Oct 2011 at 17:00 GMT
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DennisS said: Smooth said: I use a remote!
Kind of hard with a monopod.
I've always use a remote with a monopod! One hand on the monopod the other on the remote...
You also have a self timer to help getting your hand out of the way!
Regards, Smooth
www.omnipix.com.au
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