V2 HQ Housing Assembly Focus issue

StereoPi v2 hardware questions
Post Reply
joedevivo
Posts: 8
Joined: Tue Oct 12, 2021 2:55 pm

V2 HQ Housing Assembly Focus issue

Post by joedevivo »

I've finally got everything working but my images are too blurry to do anything with. I'm using two HQ camera modules with two 16mm official raspberry pi telephoto lenses. I am able to get them to focus if I significantly loosen the lenses, but then they're too loose to stay where they are. Any ideas how to fix this. Am I missing some part?
919553CA-DAD5-48E3-B21B-30567E2AEAFC_1_105_c.jpeg
919553CA-DAD5-48E3-B21B-30567E2AEAFC_1_105_c.jpeg (210.27 KiB) Viewed 1812 times
D0BD70BC-F906-4244-9EA6-1B7BC47D36AE_1_102_a.jpeg
D0BD70BC-F906-4244-9EA6-1B7BC47D36AE_1_102_a.jpeg (558.7 KiB) Viewed 1809 times
6F74D4D0-1FFB-4DC5-8366-89130B31553D_1_105_c.jpeg
6F74D4D0-1FFB-4DC5-8366-89130B31553D_1_105_c.jpeg (148.62 KiB) Viewed 1809 times

User avatar
Realizator
Site Admin
Posts: 805
Joined: Tue Apr 16, 2019 9:23 am
Contact:

Re: V2 HQ Housing Assembly Focus issue

Post by Realizator »

Hi joedevivo,
The issue is that the 16mm lens is C-mount, and has a different working distance. You can notice that HQ camera has a special black ring to adjust this distance, and this led to difficult solution with additional components and threads.
The easiest solution is to use an appropriate C-CS adaptor ring. As I see on your photo, you are using the 5mm ring provided with the HQ camera or 16mm lens. The ideal ring height for 16mm lens is 7-8mm. If you have no this kind of a ring, you can use this kind of set with a few 2mm or 3mm rings to adjust the height of your 5mm ring.
Eugene a.k.a. Realizator

joedevivo
Posts: 8
Joined: Tue Oct 12, 2021 2:55 pm

Re: V2 HQ Housing Assembly Focus issue

Post by joedevivo »

fantastic. should I pick up a 7 or 8mm ring? Would that also work for Arducam's 8mm lens?

User avatar
Realizator
Site Admin
Posts: 805
Joined: Tue Apr 16, 2019 9:23 am
Contact:

Re: V2 HQ Housing Assembly Focus issue

Post by Realizator »

joedevivo, long story short - 8mm.
When you fully screw in a 16mm lens using the 8mm ring, you get a good focus with the approximate "middle" position of the "far-near" regulation ring on the lens. It means you have some reserve for adjusting the focus in both directions.
I prefer using the smaller ring thickness (5mm or 7mm) and additional 1mm rings for precise positioning. Yup, it means more stuff but more flexibility.

As for the Arducam's 8mm lenses - I did not play with this. Theoretically, you can find the datasheet and compare the working distance parameters for RPF 16mm and Arducam's 8mm lenses. I'd do this before buying the ring to avoid additional purchases later. :)
Eugene a.k.a. Realizator

joedevivo
Posts: 8
Joined: Tue Oct 12, 2021 2:55 pm

Re: V2 HQ Housing Assembly Focus issue

Post by joedevivo »

Thanks again. If I'm doing the math right, that means that the HQ housing assembly is providing around 9-10mm of extension on it's own, and the 8mm ring is getting us to the approximately 17.53mm that the 16mm lens wants.

If that's correct, then the 8mm lens only wants 7.53mm, which means that no matter what I do, it'll be too far from the sensor, does that sound right?

Actually, it looks like it's the same as the 6mm official pi lens, so if you know the ring size I need for that, we're all set.

User avatar
Realizator
Site Admin
Posts: 805
Joined: Tue Apr 16, 2019 9:23 am
Contact:

Re: V2 HQ Housing Assembly Focus issue

Post by Realizator »

"Official" 6mm lens (recommended by RPF) are CS-mount, and they are working fine with the HQ housing without C-CS adaptor ring.
Eugene a.k.a. Realizator

joedevivo
Posts: 8
Joined: Tue Oct 12, 2021 2:55 pm

Re: V2 HQ Housing Assembly Focus issue

Post by joedevivo »

Ha, then my math is definitely off. What number should I be looking at for the working distance on the two RPF lenses? I can use that to kind of figure out what's going on the Arducams.

What I was able to do is put the 6mm ring on and the RPF 16mm loose enough to focus, then measured the gap with calipers and yeah, its about 2mm. When I do the same with the Arducam 8mm, I get the same gap within 0.5mm, so hopefully the 8mm will solve for both.

I'll report back when they arrive this weekend.

User avatar
Realizator
Site Admin
Posts: 805
Joined: Tue Apr 16, 2019 9:23 am
Contact:

Re: V2 HQ Housing Assembly Focus issue

Post by Realizator »

joedevivo, you intrigued me with your 6mm lenses issue.
Did you try to tighten the iris fixing screw and rotate the very top ring after that? This adds one more level of focus freedom for the 6mm lens :-)
Could you please share a photo of the 6mm lenses installed?
In my photo, you can see two 6mm lenses focused without the C-CS adaptor ring.
IMG_3183.jpg
IMG_3183.jpg (1.59 MiB) Viewed 1719 times
Eugene a.k.a. Realizator

User avatar
Realizator
Site Admin
Posts: 805
Joined: Tue Apr 16, 2019 9:23 am
Contact:

Re: V2 HQ Housing Assembly Focus issue

Post by Realizator »

p.s. Here is the photo which can clarify the 6mm lens adjustment margin. This feature in not obvious from the official datasheet for this lens. Look at the left lens here:
IMG_3184.jpg
IMG_3184.jpg (1.71 MiB) Viewed 1717 times
I mean other lenses might have the same "feature" of extra adjustment.
Eugene a.k.a. Realizator

dnaman
Posts: 15
Joined: Mon Oct 18, 2021 12:42 am

Re: V2 HQ Housing Assembly Focus issue

Post by dnaman »

Eugene, every time I look at those pictures (and my 6mm lenses do the same thing of course) it seems totally wrong to me to have to unscrew the lens like that simply to achieve the infinity position (and farther still to focus on anything closer).

On mine, it looked like it was open about 5mm so I tried a 5mm C/CS adapter but that was too much. (Also the 6mm lens doesn't screw fully home in the adapter because of the step in the adapter bore).

I do have some 1mm and 2mm adjustment rings on the way but since they are rings, they will take up thread length on the lens and may be impractical.

As far as I can see, a better way to do it would be to shorten the height of the bosses on the lens mounting plate. Is it possible to buy the mounting plate(s) separately?

User avatar
Realizator
Site Admin
Posts: 805
Joined: Tue Apr 16, 2019 9:23 am
Contact:

Re: V2 HQ Housing Assembly Focus issue

Post by Realizator »

Hi dnaman,

Well, that's the difference between the universal tool (with interchangeable lenses option) and the usecase-optimized solution. If you are focused on using 6mm lenses only, adjusting the mounting plate for your specific case may be the best way.
dnaman wrote:
Wed Jan 12, 2022 10:38 pm
Is it possible to buy the mounting plate(s) separately?
All HQ housing kits we have now are "kitted", since I was not sure anyone will need some specific parts of them. But I can disassemble a few kits to get spare parts.

As you are the second user who asked me for a very specific part of HQ housing, I can do a personal proposal for you. Please write me an email. :)
Eugene a.k.a. Realizator

Post Reply