SDM camera separation help

twinshot

36

« on: 07 / April / 2011, 06:51:18 »

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Hi all, i am using SDM, and have read all the tutorials, but i don't quite understand the purpose of setting of camera separation settings in the stereo menu. my lens separation varies quite a bit when i am shooting stereo. what difference( if any) does it make to the shot if you change the separation distance in the menu, sorry for my lack of understanding of this feature, but i do find some of tutorials in SDM a little to vague for my little brain, i need an idiot guide , why it does this and that, and how to change it. any chance of an idiot guide for us not so clever people.

thanks for any advise.

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Microfunguy

4037

Re: SDM camera separation help

« Reply #1 on: 07 / April / 2011, 07:49:44 »

Quote from: twinshot on 07 / April / 2011, 06:51:18

i don't quite understand the purpose of setting of camera separation settings in the stereo menu.

The amount of depth in a stereo image depends on camera separation and lens focal length.
If the stereo depth is too great, the image becomes uncomfortable or impossible to view.
If you line-up the nearest subjects in the image, the distant subjects should not be separated (the 'stereo deviation') by more than about 1/30th of image width.
There are tools in SDM that will visually show you the deviation.
However, most people just want to press the button and capture the shot.
In that case, you should work with a fixed focal length of 50mm equivalent or slightly wider and find out what the nearest subject distance should be for the camera separation.
It will be about two metres if infinity included, otherwise nearer.

If you do not work with fixed focal length and camera separation the stereo deviation of your images will be hit-and-miss.
You have to get to know your fixed system.

As you increase the camera separation you should also use a longer focal length to reduce excessive deviation.
Problem is, that gives you a pop-up book cardboard cutout effect with few depth planes.

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any chance of an idiot guide

Not if I want to spend time taking stereo photos just like you can do.

HOWEVER, I can publically announce that member 'achilles' has agreed to spend time reworking the website documentation ... haven't you ?

« Last Edit: 07 / April / 2011, 10:23:02 by Microfunguy »

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achillies

227
SX130IS

Re: SDM camera separation help

« Reply #2 on: 07 / April / 2011, 13:00:44 »

Yes, Yes I did! Lately my mother has been having house "issues", so I've been spending more time doing repairs than anything else. But as Yul Brynner said while playing the Pharoah - "so it shall be written, so it shall be done!"

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Don't let the sands of time get in your lunch.

twinshot

36

Re: SDM camera separation help

« Reply #3 on: 07 / April / 2011, 15:47:58 »

Thanks for the reply David, i know about photo separation, i try to go for the 1-30 rule. i think you have answered my question, that changing the distance setting in SDM has no effect for the shot taken correct,? it is there to show you the deviation if you wish to view it? quote ,There are tools in SDM that will visually show you the deviation. i have also been searching for a way to set the iso lower than canon mode, but i cant seem to find it in SDM ,is there a way of doing this? thanks. i look forward to the new idiot friendly guide, thanks for taking the time achillies.

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Microfunguy

4037

Re: SDM camera separation help

« Reply #4 on: 08 / April / 2011, 06:54:13 »

ISO override is not supported by SDM because I am not convinced that it works.

Of course, feel free to post original full-size examples taken with CHDK that clearly demonstrate the benefits of a lower-than-normal ISO.

David

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twinshot

36

Re: SDM camera separation help

« Reply #5 on: 08 / April / 2011, 17:03:13 »

OK David,that explains why i couldn't find it,i thought the sun was getting to me. This was my problem,i set out to take some shots of a waterfall in the slow shutter mode,1/30( it was a very sunny day),i put the ND to kick in,and also the canon EV as low as it would go,but the shots were still far to over exposed, so i looked to set the ISO.lower than the canon which is 80. so you don't think the ISO would not have sorted the problem then? its a pain not having an AV on the 480. can you think of any other way i could have got my shot? i will probably have to give it another go when its not so bright and sunny. thanks again for any advice, i am really enjoying SDM.

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Microfunguy

4037

Re: SDM camera separation help

« Reply #6 on: 08 / April / 2011, 21:04:16 »

No point putting the ND in, the Canon firmware intended to put it in anyway as it was bright.

SDM constant exposure ND mode is useful for 8x longer exposures ... in DULL conditions !
You would have to fit an external ND filter, easy on cameras that have a lens accessory adapter.

I have no idea if a low ISO override would enable longer exposures.

Try it with CHDK and let me know.

David

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SkyWalker9

301
SX20 IS (fw 1.02b)

Re: SDM camera separation help

« Reply #7 on: 09 / April / 2011, 00:00:53 »

Quote from: twinshot on 08 / April / 2011, 17:03:13

...this was my problem,i set out to take some shots of a waterfall in the slow shutter mode,1/30( it was a very sunny day),i put the ND to kick in, and also the canon EV as low as it would go,but the shots were still far to over exposed, so i looked to set the ISO.lower than the canon which is 80. so you don't think the ISO would not have sorted the problem then? its a pain not having an AV on the 480. can you think of any other way i could have got my shot? i will probably have to give it another go when its not so bright and sunny...

@twinshot, you might want to try adding an external +4 or +8 ND lens filter. I routinely use ND filters when taking waterfall shots with my SX20. I know of at least one lens adapter available for your A480. Here are some links you might want to check out:

Zeikos Universal Lens Adapter for Canon PowerShot A480 (http://www.amazon.com/Zeikos-Universal-Adapter-PowerShot-Digital/dp/B002RBR0TE ) One reviewer's comment: "This lens adapter works as advertised for the camera models it says it supports. Worked with my Canon SD780 IS. I used it with an ND filter."
- Attaches auxiliary lenses, filters, step-rings, and more
- Anti-slip rubbers design increases its stability by increasing friction between adapter and platform
- Mounting thread: 37mm
- Material : Aluminium, NBR
- Compatible with most compact Digital Point & Shoot Cameras on the market

Some other other things to "wet the appetite"...

37mm filters: Zeikos ZE-FLK37 37mm Multi-Coated 3 Piece Filter Kit (UV-CPL-FLD) (http://www.amazon.com/Zeikos-ZE-FLK37-Multi-Coated-Filter-UV-CPL-FLD/dp/B001KN8V2U/ref=pd_sim_p_6 ) Zeikos 37mm Glass Multi Coated 3 piece Filter Kit consisting of an Ultra Violet (UV), Circular Polarizer (CPL), and a Fluorescent (FLD) Filter. They have Silver metal rings to match most cameras. Protective hard case included.

Although 37mm screw-in filters are available, they aren't as common as the 52mm & 58mm filters, so you might want to also get a step up 37mm adapter like one of the following: Fotodiox Metal Step Up Ring, Anodized Black Metal 37mm-58mm, 37-58 mm (http://www.amazon.com/Fotodiox-Metal-Anodized-Black-37mm-58mm/dp/B001G46ZN0/ref=pd_cp_p_2 ) or Adorama Step-Up Adapter Ring 37mm Lens to 52mm Filter Size (http://www.amazon.com/Adorama-Step-Up-Adapter-Ring-Filter/dp/B0002GVX7Q/ref=pd_cp_p_3 )

There's even a wide angle & telephoto lens kit available. Zeikos Universal Lens Adapter with 0.5x Wide Angle & 2x Telephoto Lenses + (3) Filters + Accessory Kit for Canon PowerShot A480 (http://www.amazon.com/gp/product/B002USQTAK/ref=pd_lpo_k2_dp_sr_2?pf_rd_p=486539851&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B002RBR0TE&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0X29JTYNTDNQ952KJQCH ). KIT INCLUDES 4 PRODUCTS -- All Brand New Items with all Manufacturer-supplied Accessories + Full USA Warranties:
- Zeikos Universal Lens Adapter for Compact Digital Cameras +
- Digital Concepts 0.5x Wide Angle & 2x Telephoto Camera/Video Lens Set +
- Zeikos 3-Piece Multi-Coated Glass Filter Kit (37mm UV/FLD/PL) - Silver +
- Precision Design 5-Piece Lens Cleaning Kit

Just some things that might help...

« Last Edit: 09 / April / 2011, 00:08:11 by SkyWalker9 »

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twinshot

36

Re: SDM camera separation help

« Reply #8 on: 09 / April / 2011, 10:23:20 »

thanks for both replies guys,i will check out the external lenses, i also tried EV lock in canon mode then turning the TV override on, that was no good either. David i am a bit reluctant to try CHDK after the mess i made trying to get SDM on my card.can i put it on there along side SDM? But then i think there would be to many menus for my brain to digest,i have enough trouble reading between the lines so to speak with SDM, tutorials.

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Microfunguy

4037

Re: SDM camera separation help

« Reply #9 on: 09 / April / 2011, 10:52:09 »

Quote from: twinshot on 09 / April / 2011, 10:23:20

can i put it on there along side SDM?

Yes.
Rename your exising file to DISKBOOT.BIN.SDM and copy the CHDK DISKBOOT.BIN to the card.

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i think there would be to many menus for my brain to digest

I agree but just learn enough to test the CHDK ISO override.

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i have enough trouble reading between the lines so to speak with SDM, tutorials.

achillies will eventually help to make that easier.

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