Forum: Tips & Tricks

Thread: samyang 7,5 m.m. specifications

back to threads list | this thread is closed
Search the forums:
messages 46-60 of 124
first prev prev 2 3 4 5 6 next next last
Author  Message 
DennisS

Posts: 1787
Location: Los Anglels, United States
Registered: 1 Sep 2007
Re: samyang 7,5 m.m. specifications
Posted: 13 Sep 2011 at 22:06 GMT
updated: 13 Sep 2011 at 22:09 GMT
I get .058" to .060" on the actual flange, not the overall height. I think that works out to 1.473mm to 1.524mm. I never do the metric conversion, so I could be wrong.

This is one solid feelng adapter. It feels way more secure and solid than the Nikon/NEX adapter I am currently using.

I wish the USPS would hurry up and GET ME MY LENS!
alert moderator
jannefoo

Posts: 61
Location: Finland
Registered: 3 Jun 2009
Re: samyang 7,5 m.m. specifications
Posted: 13 Sep 2011 at 22:07 GMT
Geometrically the images are very similar to the 8mm version and 4+1 sphericals are possible on MFT cameras.

alert moderator
juann

Posts: 142
Location:
Registered: 6 May 2006
Re: samyang 7,5 m.m. specifications
Posted: 13 Sep 2011 at 22:30 GMT
Thanks Smooth and Denniss , I think would be more 1,25 m.m. than 2 m.mCould you post where did you bought adapter.
Juan
alert moderator
DennisS

Posts: 1787
Location: Los Anglels, United States
Registered: 1 Sep 2007
Re: samyang 7,5 m.m. specifications
Posted: 13 Sep 2011 at 23:00 GMT
updated: 13 Sep 2011 at 23:03 GMT
www.ebay.com/itm/M4-3-Micro-four-third-lens-Sony-...

Search eBay for Sony 4/3 adapter.
alert moderator
Smooth

Posts: 4310
Location: Mount Panorama, Australia
Registered: 21 Jul 2004
Re: samyang 7,5 m.m. specifications
Posted: 14 Sep 2011 at 6:23 GMT

juann said:

Thanks Smooth and Denniss , I think would be more 1,25 m.m. than 2 m.m Could you post where did you bought adapter.
Juan
Mine came from this ebay seller
www.ebay.com.au/itm/Micro-4-3-M43-Sony-Nex-Adapto...
They claim INFINITY focus is guaranteed in the auction spiel. Not sure what that's worth though!

Yes, still waiting on lens delivery...

Regards, Smooth cool
www.omnipix.com.au
alert moderator
juann

Posts: 142
Location:
Registered: 6 May 2006
Re: samyang 7,5 m.m. specifications
Posted: 15 Sep 2011 at 0:49 GMT
Thanks Smooth and Denniss . New fast test without sunshade:Ptgui dates:F. length:8,015 , HFV:165,7 . 3 photos to cover 360º , Nex 5, max width:8812 , equi and one photo: www.megaupload.com/?d=A15HULTQ
Realize lens can´t focus properly because adapter.
Juan
alert moderator
Smooth

Posts: 4310
Location: Mount Panorama, Australia
Registered: 21 Jul 2004
Re: samyang 7,5 m.m. specifications
Posted: 15 Sep 2011 at 7:40 GMT
Hello Juann,

My lens arrived today and my tests show the same problem as you are experiencing. The potential is there, but without focus it is useless. I've only spent 5 minutes (literally) with the lens and I'm not awake enough to make much more of it at this stage.

Regards, Smooth cool
www.omnipix.com.au
alert moderator
Smooth

Posts: 4310
Location: Mount Panorama, Australia
Registered: 21 Jul 2004
Re: samyang 7,5 m.m. specifications
Posted: 15 Sep 2011 at 7:53 GMT
OK, quick test...

If I remove the m43 adapter and hold the lens to the body of the NEX I can get focus. This all points to the adapter pushing the lens too far away from the sensor.

Next job is to find out how to reduce the distance using an adapter.

Regards, Smooth cool
www.omnipix.com.au
alert moderator
juann

Posts: 142
Location:
Registered: 6 May 2006
Re: samyang 7,5 m.m. specifications
Posted: 15 Sep 2011 at 7:56 GMT
sad you have the same problem.Can you test lens at m4/3 body? I tried at some stores but don´t let me put lens at cameras devil .
alert moderator
Smooth

Posts: 4310
Location: Mount Panorama, Australia
Registered: 21 Jul 2004
Re: samyang 7,5 m.m. specifications
Posted: 15 Sep 2011 at 8:07 GMT
Looks like there is scope to machine the back plate (mounting plate) on the Samyang the distance/thickness of the adapter.

My initial thoughts were to drill the three screw holes and mount the adapter directly (in place) of the Samyang back plate. But you soon discover the difference in plate thickness.

Dennis plays machine shop so he might have some idea. I would have to throw it to my engineer and he isn't known for speed. Quality yes, speed not-so-much!

Regards, Smooth cool
www.omnipix.com.au
alert moderator
Hans Nyberg

Posts: 2874
Location: Denmark
Registered: 28 Aug 2005
Re: samyang 7,5 m.m. specifications
Posted: 15 Sep 2011 at 8:23 GMT

juann said:

Thanks Smooth and Denniss . New fast test without sunshade:Ptgui dates:F. length:8,015 , HFV:165,7 . 3 photos to cover 360º , Nex 5, max width:8812 , equi and one photo: www.megaupload.com/?d=A15HULTQ
Realize lens can´t focus properly because adapter.
Juan


I do not understand how you can get 165 HFOV.
How did you set the cropcircle.

This is a simulation of how it should look on the Nex.
The image is one of the 4/3 images from the test panos.


Your image shows that the circle is larger and that means that the FOV of the circle has to be around 190 degrees.

Hans
alert moderator
Smooth

Posts: 4310
Location: Mount Panorama, Australia
Registered: 21 Jul 2004
Re: samyang 7,5 m.m. specifications
Posted: 15 Sep 2011 at 8:34 GMT

juann said:

sad you have the same problem.Can you test lens at m4/3 body?
We have the same problem with stores. Unless you happen to know the owner very well, they don't allow you to try things or shoot images within the store. sad

More testing has shown if you remove the back plate of the Samyang you have access to 3 brass spacers. Removing these helped improve the focus on the NEX because the optics are being moved closer to the sensor.

Also of note the adapter is not as tight as it could be. Manually holding the lens tight to the adapter whilst fitted to the NEX improved the focus even more. These tests were at f/5.6

Now I'm going to drill the adapter the same three holes and make the adapter a part of the lens (so to speak). This will tighten everything up and hopefully give enough to allow for use.

Either way, I'm 99.9% sure I can get a result using this lens on the NEX.

Regards, Smooth cool
www.omnipix.com.au
alert moderator
juann

Posts: 142
Location:
Registered: 6 May 2006
Re: samyang 7,5 m.m. specifications
Posted: 15 Sep 2011 at 9:01 GMT
Sorry a mistake, HFV: 185,4 , F.L: 8,1 m.m

Hans Nyberg said:

juann said:

Thanks Smooth and Denniss . New fast test without sunshade:Ptgui dates:F. length:8,015 , HFV:165,7 . 3 photos to cover 360º , Nex 5, max width:8812 , equi and one photo: www.megaupload.com/?d=A15HULTQ
Realize lens can´t focus properly because adapter.
Juan

I do not understand how you can get 165 HFOV.
How did you set the cropcircle.

This is a simulation of how it should look on the Nex.
The image is one of the 4/3 images from the test panos.


Your image shows that the circle is larger and that means that the FOV of the circle has to be around 190 degrees.

Hans
alert moderator
juann

Posts: 142
Location:
Registered: 6 May 2006
Re: samyang 7,5 m.m. specifications
Posted: 15 Sep 2011 at 9:52 GMT
tested again without 4 spacers , I think it´s solved,captures:up Samyang 8m.m. at 3,5 and 5,6 (from left to right.Downconfusedamyang 7,5 at 3,5 and 5,6 (from left to right)www.megaupload.com/?d=GGXOAJO3
alert moderator
Smooth

Posts: 4310
Location: Mount Panorama, Australia
Registered: 21 Jul 2004
Re: samyang 7,5 m.m. specifications
Posted: 15 Sep 2011 at 10:07 GMT

juann said:

tested again without 4 spacers , I think it´s solved.
Yes, as I suspected bringing the lens optics closer to the sensor is making the improvement. I have just finished drilling and mounting the M43 adapter to the Samyang. It is now "rock solid" I removed the "three" brass spacers that were in my Samyang 7.5mm and now after two simple hyperfocal tests on my focus chart I can get good focus at f/5.6 thru f/8.0 on the lens Infinity scale mark. The chart distance in this early test is 110cm from the focal plane.

So far, no modifications have actually been made to the lens at all.

I still believe I can get it even better by shaving the equal amount of thickness of the M43 adapter from the face of the Samyang mounting plate.

Juann, you say you had 4 spacers? Mine is only 3 spacers. I guess these are how they are calibrating the lens?

This is turning out to be a winning combination.
I need to shave me lens now!

Regards, Smooth cool
www.omnipix.com.au
alert moderator
messages 46-60 of 124
first prev prev 2 3 4 5 6 next next last