Author Topic: Newbie Questions  (Read 2772 times)

mshetzer

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Newbie Questions
« on: February 24, 2021, 09:09:55 AM »
I'm a wildlife photographer, and just trying to figure out the Chronos 2.1, and have some questions I hoping someone can help me out with.

  • Do I need to use the 5mm spacer?  I'll be shooting Nikon lenses, from macro to 600mm, all primes.  How do you determine if you need the 5mm spacer and what does it correct?
  • Does anyone use an Expo Disk for White Balance?
  • Does the 2.1 have Crop sensor, and if so, what is the magnification?  Seems to be more magnification on my Nikon 200mm macro.
  • Is there a Histogram that can be turned on?  I see the zebra stripes, but looking for more exposure feedback.
  • Can I use shutters angles between 180 and 360 or is it best to stay at 180 or 360.
  • Do I need to do new Black Calibration when changing shutter angle?  I'm trying to balance the exposure remotely.

Thanks in advance for the help !
Matt

mklinger

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Re: Newbie Questions
« Reply #1 on: February 24, 2021, 09:28:52 AM »
Hi Matt,  I can try and answer most of your questions.

1.  The 5mm spacer is to account for proper focusing, usually at infinity.  This will depend on the lens.  The best way is to just check with the specific lens you want to use and see if you can focus properly.

2.  I haven't used an Expo Disk for white balance, but I've definitely used a x-rite color checker which has a proper white balance chip.  I like to shoot Cinema DNG with my Chronos 2.1 and do proper color balance/correction in post.

3. The Chronos 2.1 has what is effectively a 2x crop sensor compared to 35mm full-frame.

4. Unfortunately there is no exposure Histogram.  Hopefully that is something that can be added to the software at some time in the future as it would be nice to have.

5. Shutter angle on the Chronos is no different than any normal video shooting.  Around 180 deg gives you a very natural look to video wrt motion blur, but it's not a hard rule.  I would generally try and stay away from 360 deg shutter, but if you are shooting at extremely high speeds, that might be the only option.  It will be a tradeoff for "look" compared to boosting the gain that degrades the quality.  It's best to experiment a bit.

6.  You shouldn't have to do a black calibration after changing the shutter angle.  You definitely need to with changing resolutions and frame rates, and wait until the camera is fully warmed up for best results.   Also, search for my post on optimal horizontal resolutions, there are really only 4 base horiz resolutions on the 2.1: 1920, 1472, 1152, and 832.  Everything else won't gain you anything wrt speed - only file size, and would be the same as cropping in post.

Nikon1

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Re: Newbie Questions
« Reply #2 on: February 24, 2021, 10:19:24 AM »
#EDIT#: Was typing my reply so long, mklinger was faster than me actually, Will still post the Full thing i wrote here, even though he answered most of the things allready, but i think especially some of the Details i wrote could still be very usefull. #/EDIT#
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 1. Heavily depends on what you put on there. But i assume most Lenses you would want to put on there Would be C-Mount. As the Camera itself is CS-Mount a 5mm Spacer WILL be required. CS- and C-Mount are Two different Lens Mounts, which happen to Have the Same Thread, but different Flange Focal Distances (5mm Difference, to be precise, CS-Mount beeing the Shorter of the Both). While you will be able to Mount and Use any C-Mount Lens and Adapter directly on the Camera/ CS-Mount, it will result in Problems With Focus. If you use Standard Nikon-F Mount to C-Mount adapters directly on the Camera without that 5mm Spacer, your Entire Focus Range Will Shift. Meaning now you cant focus as Close as usual and Infinity will be reached way bevore the Infinity Mark on the Lens itself, allowing focus "beyond Infinity", which will result in no sharp image at all, no matter what. Also all the Focus Distance Markings on the Lens will be absoutely invalid if used in such a way. Now, this is Less of a Problem with Super-Tele Lenses, but for Normal, Wide or Superwide Lenses this effect can be so extreme that you wont be able to get anyting in focus ever with this Lens, no matter the Focus Setting on the Lens itself. Hope this explains this well enough, for further information on CS- / C-Mount Cross Compatibility have a look at (Still Feel Free to ask, if this didnt fully answer your Question, i can go more into depth about this):
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 https://en.wikipedia.org/wiki/C_mount#CS_mount
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 3. The 2.1 Has a Crop Sensor. At Full Resolution the Sensor Size is 19,2x10,8mm, resulting in a Image Diagonal Size of ~22,03mm. This means Crop Factor compared to 35mm Full Frame (3624 mm; 43,27mm Diagonal Size) would be 1,964x (at which point you can basically call it 2x Crop). Crop-Factor / Used Sensor Size However Changes if you change Resolutions, so keep that in mind, if you end up using anything else than full resolution and need a Specific Field Of View or Focal Length. This Whole Topic about Sensor Size and How it Changes with Resolutions has been Discussed in Quite a bit of detail here:  .
 https://forum.krontech.ca/index.php?topic=619.0
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 4. Sadly No. I also allready asked about that, but it hasnt been implemented in the Software so far, and i dont know if we can expect one anytime soon. What i currently use, is an External Monitor (i personally use the SmallHD 502 Bright, but other People use a bunch of different ones too, anything with an Histogram and HDMI Will work, if this is the only requirement, there also pretty affordable ones available) and have an Histogram shown there, which Helps A LOT in exposing propperly with this camera, can reccomend. Would be nice if we get some form of Exposure Indication or even Histogram Once, but for now, an External monitor Works out great for me, also helps with focusing, and has a lot better colors than the Internal Screen (also Sharper than the Internal Screen).
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 5. Also Highly depends on what you are shooting, how much light you have available (also Lens Speed), and if Motion blur is going to be an big issue. Thing about 360 vs 180 Shutter is, that if you shoot at 360 and Play it back at lets say 24 or 25fps and have something reasonably fast moving in frame, you will get a ton of Motion Blur. 180 Has been used for basically ages in the Cinema World (Action stuff is sometimes Shot on even Shorter Shutter Speeds like 90 to make it feel Harsher and more intense), and thats why it is usually referred to as the "normal Look" when it comes to filmmaking, just cause everyone is so used to it. You can Try this out your own, do some Quick Pan Shot, and use different Shutter Settings or something else Moving. Way above 180 usually feels weird (like Jello, hard to explain), and way below 180 mostly feels "choppy" for the Lack of better words for both of those. Now this doesnt mean, you must at all times use 180 no matter what. Sometimes in Reality, away from some Cinema Film set, where you will Set up for days for the Perfect Higspeed-Shot and Light everything just as needed to get it right, it comes down to actually getting footage in the First place vs. Not getting it (especially Wildlife and Nature stuff, where you sometimes just cant set up lights for things...). So if you need to, there is nothing wrong at all with using anything the Camera can handle, from 1 to 359 if it helps you get the Footage you want. I used lot of different Shutter angles for different things, but actually try to use as close to 180 as i can, if Light and the Overall situation allows for it. Of course, if you Want A lot of Motion Blur (Sparks and stuff like that), set Shutter angle as high as possible, if you want as Little Motion Blur As Possible or ideally none, use shortest Shutter angle your Available Light allows you to use.
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 6. YES! also do Black Calibrations every now and then (if you can), because the Camera will heat up after some time (about an Hour after Start Temperature is VERY Stable usually from my tests), and if you are outside, environment Temperature can also change a bit (Sun Heating the Cam up and so on, Night/Day Temperatures; Wind...), and Sensor Temperature Changes will influence Image Quality by a lot. For every Resolution OR Shutter angle Change, you need to redo black Calibration. If not, a Horizontal Line can be Visible in frame. Same For Temperature, for Idealy you would need to do a Black Calibration for every bigger Sensor Temperature Change. For Best Results i usualy also do A Black Calibration just bevore i shoot anything to make sure Sensor Temperature at Black Calibration is as Close as Possible to Temperature when actually Recording. If you controll it Remotely, it can be an issue, because for Black Calibration you will need to block the Front of the Lens from All Light. If its not possible or convenient to do full Black Calibration every now and Then, because of lack of physical Acces to the Camera, i would at least let it warm up for like 30 to 60 Minutes and Do a black Calibration directly after Boot-Up and One when its warm, after that Warm-up time (You should also be able to check Sensor Temperature Remotely, so if you wanted, you could check every now and then, if Temperature drifted away a lot or something. When Well Warmed up, like +-3 C Changes shouldnt really hurt image Quality much, especially with the new 0.6.0 Software, but the Less Light you have, the more visible it will be.
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 As with the Shutter Speed Question, you will still be able to record Footage (even without any Black-Calibration ever after Boot) without an absolutely-For-your-Shutter-Angle-and-Temperature-Valid Black-Calibration, but depending on how much you are off, it can be more or less visible. As Far as shutter Angle goes, for some Situations, when there is good Light and No Gain Involved, you can sometimes get away with changing Shutter angle without Re-Calibrating without it beeing visible or it just beeing Hardly visible at all. But Best practice is to at least Let it Warm up completely and do a Black-Calibration and do one after every Shutter-Angle Change. If you need to adjust exposure a lot remotely, it might be an better option to find a way to Remote Control the Lens Iris or some Variable ND-Filter, given there is enough light for that, and Leave the Camera set at a fixed Shutter-Angle Setting.
« Last Edit: February 24, 2021, 11:44:44 AM by Nikon1 »

mshetzer

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Re: Newbie Questions
« Reply #3 on: February 24, 2021, 10:21:13 AM »
Thanks for taking the time to provide me some help.

All makes perfect sense.

I'm certainly struggling with the WB.  I'm shooting in snow today, and highlights are getting a red hue (and catchlights in the eyes are going red as well).  I've been using a white card, and dropping exposure 1 to 2 stops. 

Do you feel the x-rite color checker would help with that?

Matt

mklinger

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Re: Newbie Questions
« Reply #4 on: February 24, 2021, 10:28:08 AM »
I think the red/pink in the snow hightlights are due to overexposure, not white balance issues.  That might be more of an issue with the latest software revision.  As with general photography, as I'm sure you're aware, it's WAY better to underexpose and bring up in post a bit than to blow out the highlights.

The sensor in the Chronos doesn't have anywhere near the dynamic range as modern DLSRs or high end video camera.  You need to be very careful not to blow out the highlights and get the exposure right.  Which is why a histogram would be so nice to have!! :)

mshetzer

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Re: Newbie Questions
« Reply #5 on: February 24, 2021, 10:47:39 AM »
Thanks for the insight.  I'm not clipped, but the snow is white, and when I'm pushing the exposure (almost clipping and not showing zebra bands) it gives a red\pink hue in the high lighted areas

've set my white balance many times (custom).  The birds are dark, so I want to make sure they are exposured correctly.

I've even set my WB on the snow, and it still comes up pink unless I under expose it by about a stop.

Thanks
Matt




Nikon1

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Re: Newbie Questions
« Reply #6 on: February 24, 2021, 10:49:27 AM »
What Gain setting are you using? Higher Gain Settings can cause blown out Highlights and weird Colors in highlights, even bevore they are technically Hard-Clipping.

mshetzer

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Re: Newbie Questions
« Reply #7 on: February 24, 2021, 11:06:59 AM »
0 gain. 

Here is an example.  I purposely let the top go to see the clip.




mshetzer

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Re: Newbie Questions
« Reply #8 on: February 24, 2021, 11:11:27 AM »
What Gain setting are you using? Higher Gain Settings can cause blown out Highlights and weird Colors in highlights, even bevore they are technically Hard-Clipping.

Nikon1, thanks for all that great information.  Day 2 with the camera and I'm creating more questions than answers.  Great fun leaning a new camera.

Matt

Nikon1

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Re: Newbie Questions
« Reply #9 on: February 24, 2021, 11:20:25 AM »
weird. Just Tried and noticed that too. i dont know if you use DNG or h.264 (=mp4), but for DNG, this should be able to be corrected in Editing. For h.264, maybe try to set Color Matrix to Custom and the Shown Settings in the Image (leave the lowest three fields alone, that is White-Balance, only the 3x3 Grid of Fields), this will give you a "Flat" Color Profile, allowing you to add more Saturation in Editing later, and this should fix the Pink Highlights. Overexposing is an Issue sometimes at High gain, but at 0dB it should be fine and not produce Pink highlights.
« Last Edit: February 24, 2021, 11:39:39 AM by Nikon1 »

mshetzer

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Re: Newbie Questions
« Reply #10 on: February 24, 2021, 11:31:59 AM »
I'm using h.264 right now.

When saving in DNG its soooooo slow.  I'm still running the SD card that came with the camera.  120/mb per second. 

I'm wondering if i can speed the saves up with running an SSD drive, or 300mb per second SD card.

Matt

Nikon1

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Re: Newbie Questions
« Reply #11 on: February 24, 2021, 11:37:03 AM »
yes, i feel you, its painfully slow. SSD will be quite a bit faster for DNG, same speed for h.264 however. There is at least one or two threads here about SSDs. Have one, but currently havent got it rigged up completely, so for Short stuff i still use SD, but for Longer Saves i use The SSD where ever possible, speeds saving up by quite a bit. Make Sure to Connect via e-Sata if you get an SSD, not USB,  because USB isnt that much faster than the SD-Card.

mshetzer

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Re: Newbie Questions
« Reply #12 on: February 24, 2021, 11:46:55 AM »
Perfect.  Thanks for the tips !!  I'm testing on birds right now, and by the time I save the first image, I've missed 3 others. 

Matt

mklinger

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Re: Newbie Questions
« Reply #13 on: February 24, 2021, 12:32:04 PM »
From your image, it definitely still looks like you're running in to overexposure issues.  It looks like maybe they didn't update the software to notify overexposure when they went to the latest software version.  The latest software trades some dynamic range for less pattern (striped) noise.

Try underexposing another full stop and see if you can fix the image in post.

As for saving, yeah, it's slow.  I use the eSATA to SSD for Cinema DNG.  It's much faster than the SD card, but the real limit is with camera hardware, not the save medium.  You'll never see the 500+ MB/sec an SSD card can actually do.

Recently I've been playing with Samba share connecting the camera directly to my wired network.  It's really handy for controlling the camera via the web interface and downloading the video is reasonably fast 10 to 20 MB/sec depending on resolution.  Very long Ethernet cable is extremely cheap, so depending on how you have things set up, maybe that's an option for some things.  Certainly not good for hand-holding birding though!