Lighting issue with Chronos 4K12

[khueluu]

Hi everyone,

I’m using a Chronos 4K12 to record an impact event at 6000 fps or above. I’ve used the same setup with other high-speed cameras without issues, but the Chronos footage is extremely dark. I’m not sure whether the problem is insufficient lighting, the lens, or something else I’m missing.

I’ve attached images of my setup and the lens I’m using. I’m new to this camera, so any suggestions or troubleshooting tips would be greatly appreciated.

Thanks in advance!

 

[hummingbirdography]

Is that a Canon EF mount lens? Those typically require an electronic mount in order to change the aperture unless it was built for cine. I'm guessing your lens is stopped all the way down, which is what happens by default when most EF mount cameras are turned off.

There are some tricks for opening the aperture back up- but you'd have to use one of your other cameras anytime you want to change it.

What I would recommend instead, is using the Chronos MFT plate in combination with one of the two original Metabones EF to MFT speedboosters

MFT Mount (Chronos 4K12) | Kron Technologies

Precision-crafted MFT mount for Chronos 4K12 cameras. Made from aircraft-grade aluminum, it ensures accurate focus with adjustable back focus. Manual control only.

www.krontech.ca

There are some alternative options out there but I can at least confirm these two boosters work great with all Chronos models:

https://metabones.com/products/details/MB_SPEF-m43-BT3/
https://metabones.com/products/details/MB_SPEF-M43-BT4/

In addition to acquiring an extra stop of light, these have a micro USB port on the side of them which you could use to draw 5V of DC power from one of your camera's USB ports, and therefor power the internal aperture control of your lens.

I believe the latest "mark 2" revision of these speedboosters discontinued that feature, and Metabones discontinued production of the originals, so you'll probably have to find them somewhere like eBay. Make sure to check the condition of the iris adjustment switch before purchasing. I own both models, and although the switches work, they feel a bit floppy. I'm guessing its prone to getting beat up due to its proximity to the lens release button.

One other nice thing about these speedboosters is I find them much easier to fine tune your infinity focus compared to swapping shims. All you need to do is rotate the booster's rear optical piece.

Hope this helps!

 

[khueluu]

Is that a Canon EF mount lens? Those typically require an electronic mount in order to change the aperture unless it was built for cine. I'm guessing your lens is stopped all the way down, which is what happens by default when most EF mount cameras are turned off.

HOLY! This is very helpful. I think my camera has a Nikon F mount. I was not aware of this before you pointed it out.


I think my plan would be to borrow a Nikon camera from somewhere to confirm that the aperture is truly the problem. If it really is, I will purchase the mount.

THANK YOU SO SO MUCH!!!!

 

[hummingbirdography]

Happy to help!

For Nikon lenses, Canon EF is still good choice of a mount because you can get an inexpensive adapter ring, meanwhile obtain infinity focus on both types of lenses. However the reverse doesn't work- you can't put a Canon lens on a Nikon F mount due to Nikon's longer flange focal distance.

The MFT & Sony plates offer the greatest adaptability thanks to their shorter flanges

Flange focal distance - Wikipedia

en.wikipedia.org

 

[khueluu]

I see. The speed booster seems a bit expensive though. Do you think it's a bad idea if I buy a second hand Nikon camera and adjust the aperture there? Might be a bit time consuming to adjust but it would cost way less, and I only have to do it once since I will use the camera in the same setup every time.

 

[hummingbirdography]

Sorry, I thought for sure you had a Canon EF mount lens there. If the variant of that lens you have is Nikon F mount, you shouldn't need to purchase anything else to open up the iris. Unlike the Canon design, you can twist the silver ring on your Chronos lens mount, and it should open up the iris for you.

On a side note, there are speedboosters available for the Nikon F mount, and Metabones is still manufacturing them. Expensive, yes, but also worth the extra stop of light for shooting high speed

 

[khueluu]

Thank you so much! How did I missed that ring. It's much brighter now.

I also will consider buying a speed booster. Seems like a good investment considering how much I'm using these in the future.