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Messages - wilheldp

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Chronos User Discussion / Re: Chronos 1.4 Footage Thread
« on: October 16, 2017, 04:41:06 PM »
I had a shitty day at work, so I came home and played with fire...

Chronos User Discussion / Re: Focusing Troubles
« on: October 09, 2017, 05:43:20 PM »
Have you tried adjusting backfocus in the camera?
I had to do it for my camera because I have different lenses.

Yes...the backfocus ring was loose when my camera arrived (C-CS mount came completely off when I tried to remove the dust cap).  When I finally figured out what I had done, I followed the backfocus adjustment procedure in the instruction manual. 

I think some of what I'm seeing is softness, and I think some of it might be my inexperience with working with video lenses.  DSLRs with auto-focus lenses have spoiled me.

Chronos User Discussion / Re: Focusing Troubles
« on: October 04, 2017, 01:50:05 PM »

Here are some shots I took yesterday at various frame rates.  Black Cal has been done on most of those resolutions, and I did a White Balance correction before shooting.

Chronos User Discussion / Focusing Troubles
« on: October 03, 2017, 05:30:38 PM »
I have shot several videos with my camera now, and I'm having a lot of trouble getting the subject in focus.  I am using the focus peaking, and try to get the greatest concentration of cyan dots on my subject, but everything I shoot seems to come up ever-so-slightly out of focus.  I rarely use the kit lens down to F1.2 (shoot mostly in bright sunlight or with Godox + Fresnel directly on subject), so I don't think tiny depth of field is my problem. 

Does anybody have any tips for proper focusing?  I'm assuming this is just a photography problem (I don't have a lot of experience with manually focusing video lenses), but I can't seem to grasp it after 20 or so videos.

Chronos User Discussion / Re: List of good (and bad) SD cards
« on: September 25, 2017, 04:08:14 PM »
I had a Samsung micro-SD card laying around from a dash cam I no longer use.  It is 128 GB, so FAT32 isn't an option.  I had the card formatted exFAT, and I can see it on both my Mac laptop and PC desktop.  I tried to use it in the Chronos today, and the camera refused to recognize the card at all (wouldn't even show up in the storage device list).  Thankfully, I had an extra 8 GB Kingston Class 10 card laying around (that I later found out was formatted FAT16 with a 60 MB partition, causing other problems described in another thread). 

Has anybody been able to format a 64 or 128 GB card in a manner when the Chronos will recognize it?  If so, how?

Software Dev / Saving, Software Request
« on: September 25, 2017, 04:02:48 PM »
EDIT: I figured out what I did wrong while writing this post.  It turns out that the SD card I was using was previously used as a boot disk for a Raspberry Pi.  While it was an 8 GB card, it had been formatted FAT16 with a 60 MB boot partition.  The behavior I describe below was what happens when you run out of space on your SD card.  I'm going to go ahead and post this for two reasons.  One is to let people know what it looks like when you try to save to a full SD card.  And Two, to make a software request that an error message be added to the camera software to let you know that your SD card is full instead of entering an endless save loop.

I got my camera today, and everything was in great shape.  Only issue was the backfocus screw not being tight (ended up turning the C-CS adapter when I installed the lens for the first time).

My first shoot was the obligatory water droplet, and everything went fine.  Marked in and out, and saved.  mp4 file works fine.

My 2nd and 3rd shoots were the obligatory lighter strike and a small firecracker exploding.  On both of these, I marked in, marked out, and hit save.  The save buffer went through the marked frames, but then it started over from 1 and went through all 8700+ frames...repeatedly.  It got stuck in an endless loop both times, and I had to hard reset it both times.  The files created during this process are corrupted and won't play.

For comparison, my successful water droplet video is 14 seconds long and ~35 MB.  The failed videos are 4 MB and 2 kB.  I think the size of those files is a function of number of frames it was at when I hard reset the camera (the second time it happened, I knew to look for it, so I reset the camera right after it restarted saving from frame 1).

Chronos User Discussion / Re: [CLOSED] Pre-orders shipping yet?
« on: September 20, 2017, 04:05:56 AM »
They said they made several extra cameras to go beyond the current orders. So your wait should be just at the end of the existing orders in front of ya.

My deliver date is tomorrow.. cant wait..

Guess I need to finally decide on a sd now.. :)

When did you order your camera?  I was a late pre-order, but I was really hoping my camera would ship early this week so I would get it before the weekend.  Alas, I still don't have a tracking number, so there is little chance of me getting the camera this week.

General high-speed discussion / Re: Measuring Speed
« on: September 19, 2017, 03:07:21 PM » ?


That might be crazy enough to work.  I could cut off some of the black strips and make 1-foot segments to put below the 1-inch segments.  I wonder how accurate their 1" strips are...not that any of this is going to be super-precise anyway.

General high-speed discussion / Re: Measuring Speed
« on: September 19, 2017, 03:58:30 AM »
Yeah, I'm starting to think that nobody sells them commercially.  The NHTSA website references "inch tape" with alternating yellow and black, 1" bands, but I couldn't find anybody selling that.  I found some photo scales on forensic supply websites, but the biggest ones I could find are 1-1/4" wide and 12 inches long.  I guess I'm going to have to make my own.  I really hate painting.

General high-speed discussion / Measuring Speed
« on: September 18, 2017, 12:39:10 PM »
Is there a proper name for the backing board that you can place behind a fast-moving subject to measure its speed?  The Mythbusters used them all the time, and I've seen them on some ping pong cannon videos too.  Basically, it is black and white lines of known width (inch/foot, or metric markings).  If you know the frame rate of the camera and playback frame rate, you can measure the exact distance that an object moves between frames, and calculate its speed.

I'd like to do some of those experiments with my Chronos.  I can probably make one, but if they are relatively cheap to buy, I'd rather go that route.  I don't have a lot of spare time at the moment, and I'd be worth it to me to just buy such a board unless they are exorbitantly expensive.  As of yet, I've failed to find a string of search terms on Google or Amazon that gets me what I want.

Chronos User Discussion / Re: Let's talk lighting
« on: September 16, 2017, 01:34:02 PM »
So looking at the Godox with the NG-10X fresnel attachment - according to an Amazon reviewer that gave about 30,000lux @ 1m, so two of those and going black-white should make f/4@4kfps more or less in range (preferably three to get down from 360 shutter...). Will continue to loo a bit more... :-)

I bought that exact setup.  I haven't had a chance to use it with the camera yet (mine will hopefully ship next week), but I did some testing on the light and lens.

Chronos User Discussion / Re: Shipping has begun on the main batch!
« on: September 01, 2017, 07:23:29 AM »
That is awesome. Congratulations on a successful Kickstarter campaign and fulfillment, David!  You have done what many Kickstarters fail to do, and although you are a little behind schedule, you are still well ahead of other fulfilled projects.  I hope your company continues to thrive now that you have completed the campaign.

So... Last we heard was that they'd go out in late August... Not to pester, but I see August is over in but a few days... How's everything looking?

The camera page in the store has been updated to read...

Existing preorders will be shipping starting August 31st, once all orders are shipped the camera will be available from stock.

I don't know if you are a Kickstarter or pre-orderer.  If you backed on KS, maybe yours will ship sooner, but it looks like pre-orders are going out on or around Thursday.  I have been checking the store page and KS updates fairly regularly, so I'd say the update to the store page was made either this past weekend or yesterday.

Since I don't have my camera yet, and I'm obsessed with it already, I decided to get a high-powered LED studio light to play with until my camera arrives.  I depends on your definition of "cheap," but in terms of studio-grade lighting, the light I bought was relatively cheap at $250 for 150 watts of LED.   I bought a Godox SL-150W and an NG-10X Fresnel lens ( and

I think the 150 watt version of the Godox SL series is the best deal.  It's only ~$15 more expensive than the 100 watt version, but $100 less than the 200 watt version.  It comes with a reflector to focus the beam, and the ~$35 fresnel lens focuses it even more.  I took several light level readings at ~1 meter using a cheap light meter.  For reference, I sat my light meter on the ground outside my house in direct sunlight at about 2 pm, and it showed a reading of ~60,000 lux.   From what I read, direct sunlight should be in excess of 100,000 lux, so either the sun was too low for my measurement, the light meter is horribly uncalibrated, or I did something wrong.  All of which are equally likely, but all of my readings were made using the same meter with the same meat-head operating it, so that should eliminate two of the variables. 

Below are my readings with the light set to 10%, 25%, 50%, 75%, and 100% power with no attachments, the included reflector, and the fresnel lens set to its lowest and highest settings.  Long story short, with the fresnel lens at its highest setting, the Godox light has roughly half of the intensity of bright sunlight.  Also, you have a pretty good spread of light levels from 700 to 30,000 lux for <$300.

Light set to 10% power:
No attachment -  700 lux
Reflector -     1100 lux
Fresnel (min) - 2500 lux
Fresnel (max) - 3500 lux

Light set to 25% power:
No attachment - 1200 lux
Reflector -     2300 lux
Fresnel (min) - 5400 lux
Fresnel (max) - 7700 lux

Light set to 50% power:
No attachment -  2100 lux
Reflector -      4100 lux
Fresnel (min) - 10000 lux
Fresnel (max) - 14500 lux

Light set to 75% power:
No attachment -  2500 lux
Reflector -      6000 lux
Fresnel (min) - 14800 lux
Fresnel (max) - 22300 lux

Light set to 100% power:
No attachment -  3800 lux
Reflector -      8000 lux
Fresnel (min) - 19400 lux
Fresnel (max) - 30000 lux

I also did a crude test for flicker.  I hooked a solar cell up to a oscilloscope, and placed it directly in front of the LED.  I measured a 40 millivolt peak-to-peak oscillation at ~100 megahertz, but I think that it was actually the noise floor of the scope that I was seeing.  There was no noticeable flicker at any but the lowest vertical resolutions on the scope, and certainly no 60 Hz flicker making it through the power supply.  The proof will be in the pudding if I see some flicker at high frame rates once my camera arrives.  Flicker was my main concern buying a cheaper LED light, and my preliminary testing has made me cautiously optimistic.

Chronos User Discussion / Re: Mounting Holes
« on: August 16, 2017, 10:36:35 AM »
Is that the Computar zoom lens you are using with this blast shield bracket?  Also, is that 1/4" acrylic over the lens?  Have you noticed any affect on the image quality shooting through the acrylic/polycarbonate?

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