Author Topic: Let's talk LENSES!  (Read 4925 times)

BiduleOhm

  • Jr. Member
  • **
  • Posts: 78
    • View Profile
Re: Let's talk LENSES!
« Reply #30 on: October 14, 2018, 01:44:52 AM »
This kind of lense usually take a 9-12 V power and the composite video signal. In short they look at the average level of the video signal to know the luminance and open/close the iris. You can see in the photo of the datasheet it's the case here and you even have the color of the wires matched with what they do. So by sending a 0 to about 1 V DC voltage at the video input you should be able to control the lense iris.

I plan to test this when I get this lens (thanks for posting the link BTW ;)) and post a simple schematic if you want to do the same.

Nikon1

  • Full Member
  • ***
  • Posts: 170
    • View Profile
Re: Let's talk LENSES!
« Reply #31 on: October 14, 2018, 02:02:09 AM »
Oh, Wow, Thanks for the info. I never knew how those Auto-Iris Lenses Worked. I also never actually owned one myself. But good to know anyways.
.
I wont buy that lens, since it is for 2/3", which is perfect for the Chronos, but wont cover the 1" sensor of my Nikon1 completely without vignetting (Just guessing). Just stumbled across this thing on Ebay and found, that it would be worth posting here since the Lens is most likely good brand Quality and quite Cheap, very wide and a good Fit for the Chronos. Also, most people would have the 12-75mm Lens, so an 5,6mm like this would be an Nice addition to anyones Camera, both for wide-Angle/ Tight spaces and also for lower Resolution/ very high-framerate Shooting.
.
If someone buys this, and happens to own some Kind of mirrorless Camera, it would be very nice if he could take an image with this lens, if the image Circle of the Lens is 15mm or bigger, i will also get one of those. Otherwise its not worth it for the use on the Nikon1 for me.

BiduleOhm

  • Jr. Member
  • **
  • Posts: 78
    • View Profile
Re: Let's talk LENSES!
« Reply #32 on: October 14, 2018, 02:27:57 AM »
There's also the ones who don't have any electronics inside (they're called DC iris; the one you posted is called video iris) and the camera do all the job, they have a 4 pins square connector instead of the mini-DIN like connector; 2 for motor and 2 for feedback (and both are coils like in a galvanometer so be careful with what you power it).


nik282000

  • Jr. Member
  • **
  • Posts: 77
    • View Profile
Re: Let's talk LENSES!
« Reply #33 on: February 01, 2019, 01:51:51 PM »
The Fujinon 2.7mm F1.8

I wanted a really wide lens so that I could get a reasonable field of view when using higher frame rates and this lens looked like it would do the job. You can find this lens on ebay starting around 150CAD, there are some sellers that have it listed for WAY more than that, it's not worth that much. If you want one keep looking and wait it out until you can find one for 200 or less.

The Good:
-It's wide! If you are using the full width of the Chronos' sensor you will get a 180degree wide field of view!
-It's fast! F/1.8 means it delivers a very bright image, it captures a lot of light.
-It's small, around 50mm long which is bigger than most c-mount lenses but WAY smaller than the SLR lenses I use.

The Bad:
-Fixed focus, there is no way to adjust the focus other than using the backfocus on the Chronos, you'll need to keep an allenkey.
-It's a little soft, being an F/1.8 it is a little soft but I didn't find it any worse than the other c-mount lenses I use.
-The price, brand new (with the adjustable aperture) it seems to go for 400 CAD and up, hold out for a used one on eBay if you can.
-Image circle, when using the full Chronos sensor the image circle doesn't entirely fill the frame, but given the field of view it's not a huge problem.


Setting the backfocus can be a little finicky, I found it was best to set the Chronos to a small crop (128x128 ish) and then adjust the focus. My copy came with a weird cap/adapter and 2 very thin plastic rings, adding just one of the rings will take the focus from infinity down to 1m or less, this lens is VERY sensitive to changes in distance between the lens and the sensor. Overall I am impressed, it's well built and despite being a little soft it more than makes up for it by giving a 180 degree field of view. For reference, in the last photo the lens is touching the glass of the window and yet you can still see the edges of the frame.
« Last Edit: February 01, 2019, 02:00:49 PM by nik282000 »

Nikon1

  • Full Member
  • ***
  • Posts: 170
    • View Profile
Re: Let's talk LENSES!
« Reply #34 on: February 02, 2019, 08:08:43 AM »
I also have that same Lens, the Fujinon 2,7mm 1.8. Mine Is also without the Aperture, because that one seemd to expensive back when i bought it.
It really is a great Lens and i always keep it in my C-Mount Prime Lens-Set when i Need an Crazy wide FOV Lens.
Got mine for somewhere Between 120 to 180€ about two Years ago. Cant remember the price Exactly.
Cant quite agree on it beeing a Soft Lens, used it on my Nikon J5, which has an 1" Sensor and 20 Megapixel and, well it is a bit soft towards the corners, but overall it can produce very sharp Images, even at such high Resolution. Could Upload Samples, if interrested, just dont have any high-Quality samples at the Moment because i use this Lens VERY rarely.
If you dont get sharp images from this Lens, check if your Focus is actually Correct, since this Lens Has somewhat of a shallow Depth of Field for beeing that wide.
I focus mine simply by unscrewing it from The C-Mount, works nice For me, since i mostly shoot handheld with it. If you plan on using it on an Tripod or alike, you are Quite Limited to whereever your Focus is, or need some percise C-Mount Rings to set The Focus Correctly. If you use The "just unscrew the Thing from the Mount"-focusing-Method, you also have an Pretty Crazy Fisheye-Macro-Lens (could produce very interresing Results with this!) which could focus up to stuff Touching the Front Lens Element and even beyond that... Just dont Drop your Lens if it comes Loose from the Unscrewing...
.
.
I also Wanted and Needed a VERY WIDE Lens (That covers my Nikon´s J5 Full 1" Sensor while not beeing fisheye) for A long time, and finaly found something, that i am Happy with.
My Azure 6,5mm f/1.4 combined with an Rehoused old German Wide-Converter, togehter producing an 4,55mm f/1.4 Non-Fisheye-Lens, covering an full 1" Sensor (15,8mm Image Circle)!
Bevore i Got /Built this, i Tried a lot of other Lenses just naming a few here:
.
- 8mm 1.4 Kowa for 1". Amazing Lens, super Sharp, extremely well built, Love this Lens, most used Lens of my very wide ones, but sometimes just not wide enough.
.
-6,5mm 1.8? TV Lens (not quite Sure anymore, what the Exact numbers Where). Got that one for 30€ on ebay, not very sharp and also produces somewhat lame Looking images, Cracked the Front Element while Trying To Manufacture a mount for an 0,7x Wide-Angle Converter. Gave it to nineff, because i allready orderd the Avenir back then. For around 30€ good value for the money, but i wasnt toooo happy about sharpness...
.
-6,7-13mm 1Nikkor Lens. Very Sharp Lens, BTW, some handsome Person could use This Lens on an Chronos or even Rehouse it. (if you want to do this, keep in mind, it is a Focus-By wire only! Lens and hasnt even an aperture dial or something, can be done with heavy Modification and/ or some workarounds, but not very fun thing to do) I Built an adapter-Clamp for my 0,7x Wide-Converter, and that worked well, but it bothered me that this lens was just an f/3,5-5,6 and therefore it was only useable in Daylight...
.
2,7mm 1.8 Fujinon. See above
.
4,2mm 1.6 Pentax. Sharp enough lens, very wide, not as Wide as the Fujinon, but stil impressive for such a small Lens. but also Fisheye. Also got this one for 30 to 40€ incl. Shipping, good Value For this price. Will make a Circular image and should even on the chronos produce images with Black corners.
.
.
And why did i finaly buy the Azure 6,5mm 1.4, and not the Kowa 6mm 1.8 or one of those old Tegea 5,9mm C-mount- Cinr Lenses and the Like?
Well, the Azure goes for around 200 used and a bit more new (maybe up to 300 including shipping), is a half stop faster than the Kowa, has an Filter Thread, on which a can Mount an Wide-Angle Converter, while th Kowa 6mm only has that Huge, Sticking out, Front Element, With which i had to worry all day about not getting it damaged, and no easy way of attatching an Wide-Converter. Also, the Kowa is a Good bit Bigger, heavier and costs about three times that what the Azure Will cost you. Kowa 6mm 1.8: New around 700, not including shipping and up to 600 used.
Those Tegea and alike are mostly overpriced and they are huge Heavy beasts of Lenses... Havent used one yet, but heard, that those also should not be the Sharpest Lenses ever made. Those Could be worth the money, if you absolutely need or want That Cinematic Look, but i doubt that.
.
So i bought the Azure 6,5mm 1.4.
This lens is Crazy Sharp, has quite some Contrast to it and an Punchy Look (very clean, not as bold of an contrasty and vibrant Look as the Kowa 8mm 1.4 has). Also, it is super small and has high overall image Quality, Low distortion, minimal Vignetting an is sharp up to the corners and covers an full Nikon 1 J5 1" Sensor without problems. I think this is the best Value for Money and also about as wide as you can get your Lens, bevore you get massive Vignetting, crazy big, heavy and Expensive Lensdesigns or Fisheye-Lenses (At least thats the case for 1" Sensors. Not sure about the bit smaller 2/3" Sensor of the Chronos, there may be an even Wider affordable Option available for that....). Somehow, this Lens Reminds me A LOT of the Cine-Nikkor 6,5mm 1,4 for 16mm Film... not just the Specs, also the Size and the Design of the Lens Body...and its Performance... Havent yet got an 6,5mm Cine-Nikkor in my hands to compare it to (Since those are Crazy rare Lenses and very expensive), but it could be a Plain Copy / Remake of the Cine Nikkor...?
.
As said, i paired this Azure 6,5mm 1.4 with an 0,7x wide-Converter in an Self Built New housing, togehter making it to about an 4,55mm 1.4 for 1", Non Fisheye.
It is sharp, but mostly in the Center. Looses some Sharpness towards the edges and also has some visible Distortion ( Still WAY better Than any Fisheye-Lens).
Since the Converter itself is also very small, the whole thing is rather compact and Light. Certainly not as good as an Good Brand Full-Frame Rectlinear Super-Ultra-Wide-Lens but also a lot smaller, Faster (f 1.4) and cheaper.
.
For Samples, just ask, im a bit to Lazy to do a ton of Images here, without knowing if anyone is actually interrested in it.