C300: Sending my camera to LucAdapters to make a speedbooster for C300 Mark III

[Cristian Mihai]

Long story short....LucAdapters from Italy will receive my C300 Mark III as test camera for a speedbooster version on the EF mount.....I have waited for years for Canon to release a an RF mount of this camera but seems its not gonna happen, so a speedbooster to make our C300mkIII a full frame camera its a big thing.....Will keep you posted about the progress here....

 

[Tom Roper]

Can the C300 mount EF-S lens series?

 

[norway]

What are the chances Canon will release a C200 MK II with RF mount before you get your camera back? :2vrolijk_08:

 

[Cristian Mihai]

What are the chances Canon will release a C200 MK II with RF mount before you get your camera back? :2vrolijk_08:

Let;s play....what retail price you think will the C200 mk II have? sort of a c300 mk III with an RF mount...

 

[cyvideo]

Long story short....LucAdapters from Italy will receive my C300 Mark III as test camera for a speedbooster version on the EF mount.....I have waited for years for Canon to release a an RF mount of this camera but seems its not gonna happen, so a speedbooster to make our C300mkIII a full frame camera its a big thing.....Will keep you posted about the progress here....

Yes, that sounds like an interesting proposition. Would be keen to see how that develops. How they can possibly make an EF to EF Speed Booster is totally beyond me? The EF mount has a 44 mm flange back distance, which is what EF lens are designed at. To have a 44 mm flange back. So no room to fit anything between the lens and the camera lens mount. Have they given you any indication as to how they are going to go about this?

Chris Young

 

[Cristian Mihai]

Yes, that sounds like an interesting proposition. Would be keen to see how that develops. How they can possibly make an EF to EF Speed Booster is totally beyond me? The EF mount has a 44 mm flange back distance, which is what EF lens are designed at. To have a 44 mm flange back. So no room to fit anything between the lens and the camera lens mount. Have they given you any indication as to how they are going to go about this?

Chris Young

This will be an internal speedbooster, inside camera....like he did it for Pocket 6k and Ursa cameras.

 

[cyvideo]

This will be an internal speedbooster, inside camera....like he did it for Pocket 6k and Ursa cameras.

Interesting. I've just had a good look at their site. I notice with all of their focal reducer adapters that the original factory IR filter has to be removed. Furthermore, I see they list a range of IR filters for this reason. But no mention of OLPF filters? This raises many questions on my part.

As far as I know, the C300 mark iii has an integrated OLPF/IR sandwich filter in front of the sensor. If this is removed, and another optical relay is placed between the lens and the sensor, I have to ask how this will affect Canon's very sophisticated Diffraction Correction system within the EOS C300 Mark III. Especially with the IR filter removed. The C300's camera processor implements real-time compensation for diffraction and for the optical pre-filtering. Only in XF-AVC mode, not RAW. A correction circuit under control of a recovery filter database within the DIGIC DV7 implements this compensation.

Quote from Canon's C300 white paper:

"The design of this database is based upon an assessment of the textural image deterioration as the light passes through the lens aperture, followed by the camera pre-filtering. This entails an analysis of the behavior of the point spread function of light beams passing through that system, which is then converted into a mathematical function – termed the optical transfer functions (OTF). This modelling incorporates the alterations to the point spread function as the lens aperture ranges from fully open to fully closed. An inverse function is then created and this forms the basis of the recovery filter database that controls the correction circuit (in real-time as the lens aperture is operated) to return the video image quality to close to the state associated with wide open aperture setting."

More here in Canon's white paper:

https://cdn-docs.av-iq.com/dataSheet/3795C002.pdf

All the lens settings are communicated through to the camera via the lens connection contacts. Obviously, there is no pre-filtering or diffraction correction information in the camera's database to compensate for the optical change in the light transmission characteristics introduced by this new booster element.

I had a long discussion with both Abakus and MTF, both lens adapter manufacturers in the UK about these sorts of issues. I use three of their adapters. They said when using manual lenses where there is no electronic communication between lens and body, it's not an issue as the database functions don't enter the question. Basically, whether you are shooting XF-AVC or RAW there are no corrections applied. How good your image is comes down to how well the adapter was designed and the quality of the lens used in each case. They both said if there was electronic communication happening between lens and body where compensation correction was involved, all bets were off as to what the results would be like. You would have to try it out for yourself, they said.

So I guess the question is, as you say, a bit of a test experiment. Extremely interested to hear how you go with this.

Thanks for being the Canary in the coalmine. Good luck Cristian. :thumbup:

Chris Young

 

[Cristian Mihai]

Interesting. I've just had a good look at their site. I notice with all of their focal reducer adapters that the original factory IR filter has to be removed. Furthermore, I see they list a range of IR filters for this reason. But no mention of OLPF filters? This raises many questions on my part.

As far as I know, the C300 mark iii has an integrated OLPF/IR sandwich filter in front of the sensor. If this is removed, and another optical relay is placed between the lens and the sensor, I have to ask how this will affect Canon's very sophisticated Diffraction Correction system within the EOS C300 Mark III. Especially with the IR filter removed. The C300's camera processor implements real-time compensation for diffraction and for the optical pre-filtering. Only in XF-AVC mode, not RAW. A correction circuit under control of a recovery filter database within the DIGIC DV7 implements this compensation.

Quote from Canon's C300 white paper:

"The design of this database is based upon an assessment of the textural image deterioration as the light passes through the lens aperture, followed by the camera pre-filtering. This entails an analysis of the behavior of the point spread function of light beams passing through that system, which is then converted into a mathematical function – termed the optical transfer functions (OTF). This modelling incorporates the alterations to the point spread function as the lens aperture ranges from fully open to fully closed. An inverse function is then created and this forms the basis of the recovery filter database that controls the correction circuit (in real-time as the lens aperture is operated) to return the video image quality to close to the state associated with wide open aperture setting."

More here in Canon's white paper:

https://cdn-docs.av-iq.com/dataSheet/3795C002.pdf

All the lens settings are communicated through to the camera via the lens connection contacts. Obviously, there is no pre-filtering or diffraction correction information in the camera's database to compensate for the optical change in the light transmission characteristics introduced by this new booster element.

I had a long discussion with both Abakus and MTF, both lens adapter manufacturers in the UK about these sorts of issues. I use three of their adapters. They said when using manual lenses where there is no electronic communication between lens and body, it's not an issue as the database functions don't enter the question. Basically, whether you are shooting XF-AVC or RAW there are no corrections applied. How good your image is comes down to how well the adapter was designed and the quality of the lens used in each case. They both said if there was electronic communication happening between lens and body where compensation correction was involved, all bets were off as to what the results would be like. You would have to try it out for yourself, they said.

So I guess the question is, as you say, a bit of a test experiment. Extremely interested to hear how you go with this.

Thanks for being the Canary in the coalmine. Good luck Cristian. :thumbup:

Chris Young

Chris...where did you see the C300 MK III has a OLPF?

 

[cyvideo]

Chris...where did you see the C300 MK III has a OLPF?

Hi Cristian.

Canon refers to its OLPF as "Optical Pre-filtering". Which is what an OLPF fiter is. To combat in band aliasing that tends to be an issue with high resolution Bayer sensors. You will see it directly referred to as the "OLPF" in the diagrams of the Canon C300 Mark III on pages #23 and #24 of the official Canon C300 Mark III white paper. This official white paper was written by Larry Thorpe, Senior Fellow, Canon USA, in 2020. He is their resident technical guru, so I tend to believe this information to be pretty accurate. A phone call or email to him at Canon USA would rapidly confirm this, I think.

Chris Young :thumbsup:

 

[Cristian Mihai]

Interesting...will check with LucAdapters if they do any removal....will keep you guys up to date...

 

[cyvideo]

Interesting...will check with LucAdapters if they do any removal....will keep you guys up to date...

Please do Cristian!

My worry is what does it do to the camera's complex compensation capabilities with a new lens group in the light path and with the removal of the OLPF and IR filter? Canon spends a lot of time and money in development of their firmware and software for their kit. With this kind of modification with lookup tables for peripheral illumination fall off and resolution restoration after pre-filtering it could raise, not saying it does, a host of curly issues. Fingers crossed.

Chris Young

 

[LightCtrl]

How has this project gone? Did you get your camera back? What was Luca adapters conclusion?

 

[morgan_moore]

every camera has an oplf does it not?

Well apart from moire hell cameras.. vintage kodak slrn and early silver box Lack Tragic.

Moiree is physics and can only be beaten by an oplf?