When focusing on infinity...?

Mark Kubat · February 8th, 2005, 05:12 PM

While the site is nicely presenting a cool concept, there are little things that have me scratching my head - like I skipped Electronics 101 in high school so as to how to wire the battery to the cd motor is NOT a given for me... guess I'll figure it out. There's also no indication really as to which macro/diopter to use: +2? +4? It depends. I'm assuming based on trying to think the optics through that the "correct" image on the disc gives you something the size of a 35mm film frame/slide - I'm wondering about trying this with a bigger lens camera like the Sony FX1 where the diameter of the lens is bigger than the radius of the CD - but of course, I don't need to have the CD spinning entirely through the camera's field of view since in actuality it's "zoomed in" on the image projected...

Mandy, how's the upside down/backwards thing and do you find if you're cradling the camera/filming while moving that "things get thrown out of whack" too quickly and you're spending your entire life re-calibrating.

One thing I wonder about this versus the other systems being presented here that maybe don't use the spinning CD trick (ie. another spinning ground glass) is that CD's do seem to spin at a very high rate and no doubt the rpm's can affect to what extent you notice "noise" on your footage. This may beg the question of if the CD motor can be tweaked to go faster... if necessary... well, I'll be in a position to try this out in a couple days...

pls. keep us updated...

Leo Mandy · February 8th, 2005, 09:35 PM

Ok, wiring the CD player is very simple. You only need two wires, but you have to determine which ones go to the CD motor, because there are a couple that are grounds and a couple that run the motor for the laser. Determine which ones by looking to see where the end off.

There was no mention of what macro he/she used. I have asked at the Mediachance site to speak to Roman, but have not got an answer yet. So without knowing, most people hear talk about 7+ or better (if I remember right).

I haven't really gone for the full housing using the project box yet, so I don't know if things are going to get thrown out of whack just yet, but I don't anticipate it. I am guessing that this will take adjusting here and there to make sure that it is working properly and the focal range is still correct.

When I zoom out with my camera, the image on the GG is really small, so that is why I am using the Telephoto lens to bring it in closer as well as a few other things that seem to be working out quite well. If the lens is big, I think you will get a better picture overall when you zoom in. Remember, you are just cropping when you zoom in closer enough and only get a small portion of the image.

The upside down thing isn't bad because all my shots are static right now - and I am using the magnet to reverse the image on the LCD. The left to right thing is tiresome during testing, but I am getting used to it.

The Spinning CD is not the best route for me, but it is the only one that works right now. One of the challenges is getting the CD to spinning vertically without 'wobble', which is apparent if you look closely at the footage. I don't know why, the CD motor works great and the CD is in good shapes besides the scratches on it. But I guess that learning will come in time.

I would personally like it to go faster, but maybe that is the problem, too fast might make it unstable and prone to more shifts (but thinking about cyntrifical force, probably not). I am using two AA batteries for mine and I can reverse the spinning direction if I need to.

I will let you know if Roman gets back to me. Have you started accumulating the items to build this machine?

Mark Kubat · February 8th, 2005, 10:54 PM

I've done some digging here and came up with posts from last year that suggest that ultimately, a spinning CD might not be fast enough, hence the development of "built-from-scratch" systems like the micro 35...

I'll be starting to round it all up within the week - just a lot going on right now...

I hadn't visited this part of the site in a long time - it's amazing to see what people are trying to do...

Some of the various clips posted show a lot of promise...

Mandy, do you have more clips?

I'll keep you posted on how things work out...

thanks!

Leo Mandy · February 11th, 2005, 05:18 PM

A question again about infinity. Is it better to have the camera on 35mm or on 105mm when focusing on infinity? I would think the closer the better (105mm) because when I used to focus on tv studio camera, we would zoom in as far as we could go, focus and zoom out - so which is better?

Oscar Spierenburg · February 11th, 2005, 07:00 PM

Good thinking, I'm sure your right about focusing best with a tele lens. It'll help me also, because I also didn't set mine on infinity too well.
The DOF artifact is much increased when zoomed in, so adjustments are best noticeable.

Leo Mandy · February 11th, 2005, 10:33 PM

Tomorrow, since I am off, I am going to be focusing (no pun intended) on getting the infinity thing right. I want to be able to put together my DOF machine and not worry about it again. Then I can start thinking about putting it a project box and getting a macro filter.

I also updated my site :

http://dvstuff.250free.com

The video was really dark because night was falling, so I boosted the levels which is why it doesn't really look normal.

Leo Mandy · February 12th, 2005, 08:50 AM

Oscar,

I did some more test today and YES it is alot better when I use the 105mm for my focus on infinity and then pull back to 35mm. Focusing is a pain as it is, the calibration is really tough, but it seems to work better at 105mm because things are alot clearly when trying to calibrate.

Website updated with new video test.

http://dvstuff.250free.com

One more thing :
Just a reminder to those that are working on this : good batteries are a MUST! I have been using a set of batteries for about 2-3 weeks and they are running fine, still some juice in them. After using my new GG, it didn't look so good and the CD spin seemed a little sluggish - BUT without the CD, it spun very fast. I thought it might have been the new GG CD. So on a hunch, I decided to change the batteries - and WOW! What a difference! All the lines and little breaks in the GG went away and the CD spun like a top. Going to keep a fresh set on hand and possible get some high energy rechargeable for this.

New footage coming with the new focus on inifinity.

BTW anyone got a recommendation for rechargeable that keep their juice and last?

Oscar Spierenburg · February 12th, 2005, 02:23 PM

Is it a little color shifting in the left of your footage?

About focusing:
It is still hard to focus really good, when you'll be actually filming. You don't have a focusing circle like photo camera's have. Somewhere on the board I mentioned a separate viewfinder, and measuring the distance with a tape measure.
But I'm thinking, maybe those laser measures are precise enough, and could be mounted on the adapter. You'll be able to point a laser on the subject, copy the distance on the lens and that's it.

I doubt if anyone is capable to pull focus on something moving out of the sharp area.

Leo Mandy · February 12th, 2005, 03:31 PM

I don;t know if there is colour shifting, maybe. I ordered a 7+ to 10+ macro filter today. I can't wait any more. I also went outside and got some footage, going to view it and see what it is like.
As for the laser measurement, tape will do the same trick like on a real production, but if you are lacking crew, I think that would be a good idea and that way you can set the barrel to the correct distance. Once you are outside of that sharpness area, you are right, there is no coming back - got to move the camera. How are thing with your system?

Oscar Spierenburg · February 12th, 2005, 06:34 PM

Mandy, thanks for asking, my adapter is almost finished. Some big things which will take some time are an anamorphic lens (I'll try to make it with a little curved acrylglass box filled with water) and a viewfinder.

Also, the colors on my tests are very nice, warm and saturated on the reds. I don't know if it's the GG I am using now, but when I test a GG with window foil, I'll know.

Leo Mandy · February 12th, 2005, 06:48 PM

Oscar, that is great that you are getting some vivid colours! I want some! I am wondering how you are getting such great and vibrant reds etc.

Are you using a macro lens? As I have said, I just ordered one, I hope that does the trick - but besides that, what are you using as GG to get such good colours going (if it is the GG)? Any other updates to your website? New pics of the machine?

Looking forward to it!

Also that anamorphic lens with the water thing sounds astounding! I would love to have a look see at it when you are ready - that is pretty ingenius - does it really work?

Oscar Spierenburg · February 12th, 2005, 07:17 PM

I really don't know yet (on everything you asked), but as soon as I know about the colours, I'll post on your GG tread.

Leo Mandy · February 13th, 2005, 08:29 AM

Last test before I get my Macro. These is no sense testing anymore, I know what needs to be done to change this and without getting the focus right or the sharpness of details, I can't get beyond the prototype stage.

http://dvstuff.250free.com

This is using my homemade GG, I like it alot better than the frosted CD that came with the DVD packs. I am going to start looking into the spray glue with different types of surfaces for this.

Oscar,

That cool. Let me know how things turn out.

Leo Mandy · February 15th, 2005, 04:36 PM

I am reading this little tidbit about lens :

Taken from the URL

http://www.digicaminfo.btinternet.co.uk/dslrlenses.htm

"Most SLR's are given as having a focal length multiplier of a certain size in order that it can be worked out what the focal length/field of view are, in 35mm terms, and this is relative to the size of sensor used. Thus Canon's 1D has a 1.3x, all Nikon, Pentax and Fuji's a 1.5x, Canon's other SLR's a 1.6, whilst Sigma's have a 1.7. The 4/3rds sensor is half the area of a 35mm frame so a 2x factor gives an equivalent focal length. So the 14-54mm standard lens fitted to the E1 equates to 28-108mm in 35mm terms. The smaller the sensor, the larger the multiplier factor will be. "

Now, because I am building the DOF machine, I have to make the Focal length adjustment myself on the fly, it is sort of hard, so I was hoping this would help. It says that Sigma's 35-105 Zoom (which I have) have a 1.7 - but 1.7 what? Inches? Cm? This will enable me to accurately set the infinity focal length.

If you look further down the chart, I can see that the Sigma falls under the 1.7 (I guess), but since mine is a 35-105mm zoom, I cannot figure out where to go from here.

When I set the infinity, I am using the 105mm and zoomed in as far as I can go, so that when I zoom back, it will be in focus.

Any help on this?

Aaron Shaw · February 15th, 2005, 05:08 PM

The 1.7 is a multiplication factor. However, it is not an issue with these adapters. It's only when 35mm lenses are used on digital SLRs which have smaller imaging areas.

February 8th, 2005, 05:12 PM	#16
Mark Kubat Major Player Join Date: Jan 2003 Location: Toronto, Canada Posts: 375	Mandy, thanks for reply... While the site is nicely presenting a cool concept, there are little things that have me scratching my head - like I skipped Electronics 101 in high school so as to how to wire the battery to the cd motor is NOT a given for me... guess I'll figure it out. There's also no indication really as to which macro/diopter to use: +2? +4? It depends. I'm assuming based on trying to think the optics through that the "correct" image on the disc gives you something the size of a 35mm film frame/slide - I'm wondering about trying this with a bigger lens camera like the Sony FX1 where the diameter of the lens is bigger than the radius of the CD - but of course, I don't need to have the CD spinning entirely through the camera's field of view since in actuality it's "zoomed in" on the image projected... Mandy, how's the upside down/backwards thing and do you find if you're cradling the camera/filming while moving that "things get thrown out of whack" too quickly and you're spending your entire life re-calibrating. One thing I wonder about this versus the other systems being presented here that maybe don't use the spinning CD trick (ie. another spinning ground glass) is that CD's do seem to spin at a very high rate and no doubt the rpm's can affect to what extent you notice "noise" on your footage. This may beg the question of if the CD motor can be tweaked to go faster... if necessary... well, I'll be in a position to try this out in a couple days... pls. keep us updated...

February 8th, 2005, 10:54 PM	#18
Mark Kubat Major Player Join Date: Jan 2003 Location: Toronto, Canada Posts: 375	I haven't started yet - but I will within the week... I've done some digging here and came up with posts from last year that suggest that ultimately, a spinning CD might not be fast enough, hence the development of "built-from-scratch" systems like the micro 35... I'll be starting to round it all up within the week - just a lot going on right now... I hadn't visited this part of the site in a long time - it's amazing to see what people are trying to do... Some of the various clips posted show a lot of promise... Mandy, do you have more clips? I'll keep you posted on how things work out... thanks!

February 8th, 2005, 09:35 PM	#17
Leo Mandy Major Player Join Date: Dec 2004 Posts: 749	Ok, wiring the CD player is very simple. You only need two wires, but you have to determine which ones go to the CD motor, because there are a couple that are grounds and a couple that run the motor for the laser. Determine which ones by looking to see where the end off. There was no mention of what macro he/she used. I have asked at the Mediachance site to speak to Roman, but have not got an answer yet. So without knowing, most people hear talk about 7+ or better (if I remember right). I haven't really gone for the full housing using the project box yet, so I don't know if things are going to get thrown out of whack just yet, but I don't anticipate it. I am guessing that this will take adjusting here and there to make sure that it is working properly and the focal range is still correct. When I zoom out with my camera, the image on the GG is really small, so that is why I am using the Telephoto lens to bring it in closer as well as a few other things that seem to be working out quite well. If the lens is big, I think you will get a better picture overall when you zoom in. Remember, you are just cropping when you zoom in closer enough and only get a small portion of the image. The upside down thing isn't bad because all my shots are static right now - and I am using the magnet to reverse the image on the LCD. The left to right thing is tiresome during testing, but I am getting used to it. The Spinning CD is not the best route for me, but it is the only one that works right now. One of the challenges is getting the CD to spinning vertically without 'wobble', which is apparent if you look closely at the footage. I don't know why, the CD motor works great and the CD is in good shapes besides the scratches on it. But I guess that learning will come in time. I would personally like it to go faster, but maybe that is the problem, too fast might make it unstable and prone to more shifts (but thinking about cyntrifical force, probably not). I am using two AA batteries for mine and I can reverse the spinning direction if I need to. I will let you know if Roman gets back to me. Have you started accumulating the items to build this machine?

February 11th, 2005, 05:18 PM	#19
Leo Mandy Major Player Join Date: Dec 2004 Posts: 749	A question again about infinity. Is it better to have the camera on 35mm or on 105mm when focusing on infinity? I would think the closer the better (105mm) because when I used to focus on tv studio camera, we would zoom in as far as we could go, focus and zoom out - so which is better?

February 11th, 2005, 07:00 PM	#20
Oscar Spierenburg Major Player Join Date: Jan 2005 Location: (The Netherlands - Belgium) Posts: 735	Good thinking, I'm sure your right about focusing best with a tele lens. It'll help me also, because I also didn't set mine on infinity too well. The DOF artifact is much increased when zoomed in, so adjustments are best noticeable.

February 11th, 2005, 10:33 PM	#21
Leo Mandy Major Player Join Date: Dec 2004 Posts: 749	Tomorrow, since I am off, I am going to be focusing (no pun intended) on getting the infinity thing right. I want to be able to put together my DOF machine and not worry about it again. Then I can start thinking about putting it a project box and getting a macro filter. I also updated my site : http://dvstuff.250free.com The video was really dark because night was falling, so I boosted the levels which is why it doesn't really look normal.

February 12th, 2005, 08:50 AM	#22
Leo Mandy Major Player Join Date: Dec 2004 Posts: 749	Oscar, I did some more test today and YES it is alot better when I use the 105mm for my focus on infinity and then pull back to 35mm. Focusing is a pain as it is, the calibration is really tough, but it seems to work better at 105mm because things are alot clearly when trying to calibrate. Website updated with new video test. http://dvstuff.250free.com One more thing : Just a reminder to those that are working on this : good batteries are a MUST! I have been using a set of batteries for about 2-3 weeks and they are running fine, still some juice in them. After using my new GG, it didn't look so good and the CD spin seemed a little sluggish - BUT without the CD, it spun very fast. I thought it might have been the new GG CD. So on a hunch, I decided to change the batteries - and WOW! What a difference! All the lines and little breaks in the GG went away and the CD spun like a top. Going to keep a fresh set on hand and possible get some high energy rechargeable for this. New footage coming with the new focus on inifinity. BTW anyone got a recommendation for rechargeable that keep their juice and last?

February 12th, 2005, 02:23 PM	#23
Oscar Spierenburg Major Player Join Date: Jan 2005 Location: (The Netherlands - Belgium) Posts: 735	Is it a little color shifting in the left of your footage? About focusing: It is still hard to focus really good, when you'll be actually filming. You don't have a focusing circle like photo camera's have. Somewhere on the board I mentioned a separate viewfinder, and measuring the distance with a tape measure. But I'm thinking, maybe those laser measures are precise enough, and could be mounted on the adapter. You'll be able to point a laser on the subject, copy the distance on the lens and that's it. I doubt if anyone is capable to pull focus on something moving out of the sharp area.

February 12th, 2005, 03:31 PM	#24
Leo Mandy Major Player Join Date: Dec 2004 Posts: 749	I don;t know if there is colour shifting, maybe. I ordered a 7+ to 10+ macro filter today. I can't wait any more. I also went outside and got some footage, going to view it and see what it is like. As for the laser measurement, tape will do the same trick like on a real production, but if you are lacking crew, I think that would be a good idea and that way you can set the barrel to the correct distance. Once you are outside of that sharpness area, you are right, there is no coming back - got to move the camera. How are thing with your system?

February 12th, 2005, 06:34 PM	#25
Oscar Spierenburg Major Player Join Date: Jan 2005 Location: (The Netherlands - Belgium) Posts: 735	Mandy, thanks for asking, my adapter is almost finished. Some big things which will take some time are an anamorphic lens (I'll try to make it with a little curved acrylglass box filled with water) and a viewfinder. Also, the colors on my tests are very nice, warm and saturated on the reds. I don't know if it's the GG I am using now, but when I test a GG with window foil, I'll know.

February 12th, 2005, 06:48 PM	#26
Leo Mandy Major Player Join Date: Dec 2004 Posts: 749	Oscar, that is great that you are getting some vivid colours! I want some! I am wondering how you are getting such great and vibrant reds etc. Are you using a macro lens? As I have said, I just ordered one, I hope that does the trick - but besides that, what are you using as GG to get such good colours going (if it is the GG)? Any other updates to your website? New pics of the machine? Looking forward to it! Also that anamorphic lens with the water thing sounds astounding! I would love to have a look see at it when you are ready - that is pretty ingenius - does it really work?

February 12th, 2005, 07:17 PM	#27
Oscar Spierenburg Major Player Join Date: Jan 2005 Location: (The Netherlands - Belgium) Posts: 735	I really don't know yet (on everything you asked), but as soon as I know about the colours, I'll post on your GG tread.

February 13th, 2005, 08:29 AM	#28
Leo Mandy Major Player Join Date: Dec 2004 Posts: 749	Last test before I get my Macro. These is no sense testing anymore, I know what needs to be done to change this and without getting the focus right or the sharpness of details, I can't get beyond the prototype stage. http://dvstuff.250free.com This is using my homemade GG, I like it alot better than the frosted CD that came with the DVD packs. I am going to start looking into the spray glue with different types of surfaces for this. Oscar, That cool. Let me know how things turn out.

February 15th, 2005, 04:36 PM	#29
Leo Mandy Major Player Join Date: Dec 2004 Posts: 749	I am reading this little tidbit about lens : Taken from the URL http://www.digicaminfo.btinternet.co.uk/dslrlenses.htm "Most SLR's are given as having a focal length multiplier of a certain size in order that it can be worked out what the focal length/field of view are, in 35mm terms, and this is relative to the size of sensor used. Thus Canon's 1D has a 1.3x, all Nikon, Pentax and Fuji's a 1.5x, Canon's other SLR's a 1.6, whilst Sigma's have a 1.7. The 4/3rds sensor is half the area of a 35mm frame so a 2x factor gives an equivalent focal length. So the 14-54mm standard lens fitted to the E1 equates to 28-108mm in 35mm terms. The smaller the sensor, the larger the multiplier factor will be. " Now, because I am building the DOF machine, I have to make the Focal length adjustment myself on the fly, it is sort of hard, so I was hoping this would help. It says that Sigma's 35-105 Zoom (which I have) have a 1.7 - but 1.7 what? Inches? Cm? This will enable me to accurately set the infinity focal length. If you look further down the chart, I can see that the Sigma falls under the 1.7 (I guess), but since mine is a 35-105mm zoom, I cannot figure out where to go from here. When I set the infinity, I am using the 105mm and zoomed in as far as I can go, so that when I zoom back, it will be in focus. Any help on this?

February 15th, 2005, 05:08 PM	#30
Aaron Shaw Major Player Join Date: Jul 2004 Posts: 587	The 1.7 is a multiplication factor. However, it is not an issue with these adapters. It's only when 35mm lenses are used on digital SLRs which have smaller imaging areas.