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Author Topic: New Hasselblad back  (Read 19752 times)
Nick-T
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« Reply #20 on: September 19, 2007, 02:08:37 PM »
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(BTW, I still don't understand what the hell Ultra-Focus is all about)
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Well I don't either so i asked a mate at 'blad and this is what he told me:

Part of the problem that was seen with adding digital backs to medium format bodies was an occasional discrepancy in focus calibration.  Ie, the position where the photographer placed the focus (manually or otherwise) could then be seen to be different in the final image.  The situation was worsened by capturing at maximum open apertures.

This could be cured by 'shimming' some digital backs (For example the Imacon Ixpress range) by the use of thin foils to bring the focus towards the correct position, albeit not always %100 accurately.

For many reasons accuracy of focus is much more critical on a CCD compared to film.

Therefore the first stage of Ultra Focus was to manufacture integrated units as 'one' as opposed to a production line of camera bodies and a line of digital units.  Yes, the digital unit can be calibrated to a 'known' position but Hasselblad feels there is still an unacceptable tolerance with this method.  Even a minimal difference in the thickness of the IR filter can change the focus position enough.  (The optimum point of focus is on the surface of the IR filter, not on the CCD below).

Therefore the first stage of ultra focus was to assemble integrated DSLR's as 'one'.  Therefore each camera was tested and calibrated as a single unit.

At the final stage the AF sensor in the H body can have an offset applied to be specifically calibrated to the digital unit.  Therefore when working the camera in AF mode you can be assured of 100% focus accuracy.  Equally using the camera in manual focus mode the AF sensor will also indicate when the subject is in perfect focus.

The next task to solve came with adjusting the AF depending on the working aperture used.  Focussing is carried out with the lens (normally) fully open.  Due to certain optical characteristics, the focus point can shift when the lens is stopped down to the working aperture.  For example, the Zeiss CF 80mm lens showed this problem quite clearly at certain distances and apertures.  

Therefore when working with an H3D the AF drive is again offset by the correct +/- amount based on the working aperture selected on the camera.

So Ultra Focus begins in the first stage of manufacture and ends in the way the AF drive is implemented.

How's that?
Nick-T
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eronald
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« Reply #21 on: September 19, 2007, 02:31:52 PM »
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How's that?
Nick-T
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How's that ?
That's clear !

Edmund
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Edmund Ronald, Ph.D. 
hcubell
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« Reply #22 on: September 19, 2007, 03:16:25 PM »
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Howard, I'll be sure to input the GPS coordinates so you can tell exactly where I was when I was testing it.  
Steve Hendrix
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This is the service I have come to appreciate from you, Steve.
Not so long ago, I could remember exactly where I had been. Not anymore.  Last year, I was in Tuscany for 10 days driving and hiking all over these dirt back roads trying to keep track of where I was shooting with a handheld GPS, a little P&S digicam and a notebook. I am seriously impressed that Hasselblad has addressed this so well.
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hcubell
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« Reply #23 on: September 19, 2007, 03:23:37 PM »
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« Last Edit: September 19, 2007, 03:25:45 PM by hcubell » Logged

BJL
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« Reply #24 on: September 19, 2007, 03:25:01 PM »
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In another forum, someone proposed a great use of "live view" from the sensor itself for calibration of the main phase detection AF system of a DSLR. Essentially, use contrast detection analysis of the image from the sensor to focus slowly but very accurately on a test subject, and compare that to what the phase detection AF system is giving. Contrast detection can be extremely accurate, and since it is measuring from the final image received from the sensor, it is immune to any of the calibration problems of PD AF.

This CD AF could be implemented only for calibration purposes and thus it would not matter if the implementation operated quite slowly. But I would actually like to see CD AF added to DSLR's for the cases where focus accuracy (and zoomable live video preview for a more detailed and accurate preview than any optical VF can give) are more important than speed.

The bottom line is the image output by the sensor, so in many ways using that output should eventually lead to the ultimate in accuracy of focus, composition, exposure levels and so on. (If done right, it is a bit like like Polaroid proofs at 24 per second!)
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hcubell
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« Reply #25 on: September 19, 2007, 04:00:42 PM »
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Well I don't either so i asked a mate at 'blad and this is what he told me:

Part of the problem that was seen with adding digital backs to medium format bodies was an occasional discrepancy in focus calibration.  Ie, the position where the photographer placed the focus (manually or otherwise) could then be seen to be different in the final image.  The situation was worsened by capturing at maximum open apertures.

This could be cured by 'shimming' some digital backs (For example the Imacon Ixpress range) by the use of thin foils to bring the focus towards the correct position, albeit not always %100 accurately.

For many reasons accuracy of focus is much more critical on a CCD compared to film.

Therefore the first stage of Ultra Focus was to manufacture integrated units as 'one' as opposed to a production line of camera bodies and a line of digital units.  Yes, the digital unit can be calibrated to a 'known' position but Hasselblad feels there is still an unacceptable tolerance with this method.  Even a minimal difference in the thickness of the IR filter can change the focus position enough.  (The optimum point of focus is on the surface of the IR filter, not on the CCD below).

Therefore the first stage of ultra focus was to assemble integrated DSLR's as 'one'.  Therefore each camera was tested and calibrated as a single unit.

At the final stage the AF sensor in the H body can have an offset applied to be specifically calibrated to the digital unit.  Therefore when working the camera in AF mode you can be assured of 100% focus accuracy.  Equally using the camera in manual focus mode the AF sensor will also indicate when the subject is in perfect focus.

The next task to solve came with adjusting the AF depending on the working aperture used.  Focussing is carried out with the lens (normally) fully open.  Due to certain optical characteristics, the focus point can shift when the lens is stopped down to the working aperture.  For example, the Zeiss CF 80mm lens showed this problem quite clearly at certain distances and apertures. 

Therefore when working with an H3D the AF drive is again offset by the correct +/- amount based on the working aperture selected on the camera.

So Ultra Focus begins in the first stage of manufacture and ends in the way the AF drive is implemented.

How's that?
Nick-T
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That's nice, but what I really need from Hasselblad is an "Ultra Depth of Field" feature(i.e., a T/S lens or two).
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Morgan_Moore
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« Reply #26 on: September 19, 2007, 04:40:12 PM »
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Well I don't either so i asked a mate at 'blad and this is what he told me................
So Ultra Focus begins in the first stage of manufacture and ends in the way the AF drive is implemented.

How's that?
Nick-T
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Highly rational and very good.

I have always been convinced that this is quite a big issue hence my like of the sinar shimming system (also on imacon)

But with no multipoint AF the whole thing goes out the window when you recompose the image which is bound to create focus errors - especially if your subject is moving and even a person standing 'still' moves

Am I not correct in thinking that the only photo I have ever seen where the subject was right in the middle was a picture of a test chart or my uncles pictures of the the christmas turkey

S
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Sam Morgan Moore Cornwall
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TechTalk
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« Reply #27 on: September 19, 2007, 06:40:08 PM »
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Highly rational and very good.

I have always been convinced that this is quite a big issue hence my like of the sinar shimming system (also on imacon)

But with no multipoint AF the whole thing goes out the window when you recompose the image which is bound to create focus errors - especially if your subject is moving and even a person standing 'still' moves

Am I not correct in thinking that the only photo I have ever seen where the subject was right in the middle was a picture of a test chart or my uncles pictures of the the christmas turkey

S
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Cameras and lenses are just tools, like a hammer or a screwdriver, that we use to make images. We survey the tools that are available and select the ones best suited to the task. We can then focus on the capabilities the tool has and how to best utilize them for our purpose or curse the tool for not being able to do what it was never designed to do.

For many photographers and their applications, the "H" autofocus works very well. The Ultra-focus program is designed to make it even better. But if what I was shooting and the way I prefer to work made multi-point autofocus a critical requirement–then I would choose a different tool.

Is it possible to design and build a multi-point autofocus system in a medium-format camera? Of course it's possible. It is all a question of money. How much would it cost to design and then sub-contract the manufacture of necessary components, spread across a low volume product market over a reasonable time frame?

The reason you haven't seen this feature on any medium-format cameras is NOT because the various camera makers are too stupid to consider it–it has been simply cost prohibitive to do. Maybe this will change in the future. For now, we look at what our tools can do and pick the best one for the job.
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pss
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« Reply #28 on: September 19, 2007, 11:10:23 PM »
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a couple of things:

leaf has had a larger then 3" display for some time now....hey maybe even phase will have one with their next backs? who cares? i can judge my exposure from my crappy P30 screen....i don't shoot 30mpix to totally depend on and do my fine tuning on 2 or 3 or even 7" displays....a nice addition but  this really should be a no brainer anyway....

there is a full line of schneider AF lenses available for the Hy6....about the same (or even more?) as the H system....

funny..i can "ultra focus" with my RZ every shot....i know what is "in focus", "acceptable focus" or simply "soft"....adding something to this range via marketing does not work for me....i have never had any problems getting "ultra focus" with my 6008 or with the RZ....i like the fact that i can leave all sharpening off in any software i work in...

ultra focus is not even close to what multi sensor AF would be....i am still amazed by claims of the "best DSLR" (according to hasselblad i assume?)...please forget a moment about your space technology billion dollar market changing 3" display and "ultra focus" and give us multi zone AF....

i still have to see in which way hasselblad provides in any way a better image then leaf, phase or sinar at the end of the day.....there are some great things about lens correction but in the end.....i don't see the advantage in print....no disadvantage either but no step up in any way.....so much for best dslr.....
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Morgan_Moore
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« Reply #29 on: September 19, 2007, 11:17:20 PM »
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Cameras and lenses are just tools, like a hammer or a screwdriver, that we use to make images. We survey the tools that are available and select the ones best suited to the task. We can then focus on the capabilities the tool has and how to best utilize them for our purpose or curse the tool for not being able to do what it was never designed to do.

For many photographers and their applications, the "H" autofocus works very well. The Ultra-focus program is designed to make it even better. But if what I was shooting and the way I prefer to work made multi-point autofocus a critical requirement–then I would choose a different tool.

Is it possible to design and build a multi-point autofocus system in a medium-format camera? Of course it's possible. It is all a question of money. How much would it cost to design and then sub-contract the manufacture of necessary components, spread across a low volume product market over a reasonable time frame?

The reason you haven't seen this feature on any medium-format cameras is NOT because the various camera makers are too stupid to consider it–it has been simply cost prohibitive to do. Maybe this will change in the future. For now, we look at what our tools can do and pick the best one for the job.
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We will obviously have to agree to disagree.

You talk absolute sense.

However

-I believe since blad started describing thier camera as a DSLR they kind of defined their 'mission' with this camera as a fast useable handheld device - something it is NOT (I would never slag a sinar P2 for not having AF)

- ths is a web forum proably read by the makers - so in some way acts as a feature requirement board - I am vocal about what I want.

 -the forum is read by potential buyers who can quickly realise whether a tool has what they need from the comments of existing users

-the forum is a forum so dont take me too serious  

-In terms of stupidity - I dont know - I think stupidity would be a gross accusation however I think they could be accused of cultural lag - The H1 was realeased at a time when MF digital backs where all tethered to a computer and operated at about 50ISO -studio tools - time has moved forward - wire free 400ISO backs mean a brave new world of portability, compact camera have face recognition AF now, the cost of microprocessing is probably 1/10th of when the H1 was concieved - roll on the H4
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Sam Morgan Moore Cornwall
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« Reply #30 on: September 19, 2007, 11:20:22 PM »
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please forget a moment about your space technology billion dollar market changing 3" display and "ultra focus" and give us multi zone AF....

[a href=\"index.php?act=findpost&pid=140605\"][{POST_SNAPBACK}][/a]

 
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Sam Morgan Moore Cornwall
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TechTalk
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« Reply #31 on: September 19, 2007, 11:58:41 PM »
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a couple of things:

leaf has had a larger then 3" display for some time now....hey maybe even phase will have one with their next backs? who cares? i can judge my exposure from my crappy P30 screen....i don't shoot 30mpix to totally depend on and do my fine tuning on 2 or 3 or even 7" displays....a nice addition but  this really should be a no brainer anyway....
[a href=\"index.php?act=findpost&pid=140605\"][{POST_SNAPBACK}][/a]
The Leaf Aptus is a fine product. I think all of the digital backs on the market are fine products–each with their own advantages and disadvantages. The screen is large, but the LCD they use has a narrow viewing angle compared to newer generation screens and, so the brightness falls off very quickly. Also, though the screen is large, the resolution is lower than the latest 3" LCD screens.

Hasselblad skipped that generation of LCD panel in the CF back series and H3D and used OLED technology instead. The screen is smaller, but there is an incredible viewing angle with no loss of brightness. Now that the LCD screens have imprroved, we can look forward to a bigger and better preview experience.

I'm glad that you "don't shoot 30mpix to totally depend on and do my fine tuning on 2 or 3 or even 7" displays". That's a wise choice. Then again, I don't know anyone that does that. It's just a preview/menu screen, but a better screen doesn't really do any harm either.
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TechTalk
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« Reply #32 on: September 20, 2007, 12:25:45 AM »
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there is a full line of schneider AF lenses available for the Hy6....about the same (or even more?) as the H system....
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Really?? Where?? I know of a 50mm, 80mm, 150mm, 180mm and 60-140mm zoom. They're listed in the 6008AF brochure. [a href=\"http://www.franke-heidecke.net/files/images/6008AF_i2_Salesguide_A.pdf]Rollei 6008AF PDF[/url]

Hy6 literature that I've seen never mention any lenses.

The "H" line is 35mm, 50mm, 80mm, 100mm, 120mm macro, 150mm, 210mm, 300mm, 50-110mm zoom and 1.7x converter–plus the 28mm for the H3D/H3D-II.

I must be missing something. I'd like to look at the rest of the autofocus Hy6 lens line, if you'd be kind enough to point me towards them.
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TechTalk
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« Reply #33 on: September 20, 2007, 12:41:12 AM »
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funny..i can "ultra focus" with my RZ every shot....i know what is "in focus", "acceptable focus" or simply "soft"....adding something to this range via marketing does not work for me....i have never had any problems getting "ultra focus" with my 6008 or with the RZ....i like the fact that i can leave all sharpening off in any software i work in...
[a href=\"index.php?act=findpost&pid=140605\"][{POST_SNAPBACK}][/a]
When they can figure out a way of getting you inside all of our cameras–it will be nothing but bright sunshiney days for all of us. Until then, the rest of us will just have to hope for continued efforts by all of the camera makers to improve on the technology as best they are able within the limits of financial viability and constraints.

I congratulate you on your focusing skills!
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izaack
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« Reply #34 on: September 20, 2007, 12:47:05 AM »
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Talking about the Hy6, has it Deep6-ed?
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TechTalk
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« Reply #35 on: September 20, 2007, 12:49:34 AM »
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ultra focus is not even close to what multi sensor AF would be....i am still amazed by claims of the "best DSLR" (according to hasselblad i assume?)...please forget a moment about your space technology billion dollar market changing 3" display and "ultra focus" and give us multi zone AF....

i still have to see in which way hasselblad provides in any way a better image then leaf, phase or sinar at the end of the day.....there are some great things about lens correction but in the end.....i don't see the advantage in print....no disadvantage either but no step up in any way.....so much for best dslr.....
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Nothing that I can add to that. You sure told them!

Now I guess Hasselblad will have to shrink away in shame or go back to designing and building the best products they can with the resources available–which will please some, not please others and leave a few really upset.
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TechTalk
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« Reply #36 on: September 20, 2007, 01:32:53 AM »
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We will obviously have to agree to disagree.

You talk absolute sense.

However

-I believe since blad started describing thier camera as a DSLR they kind of defined their 'mission' with this camera as a fast useable handheld device - something it is NOT (I would never slag a sinar P2 for not having AF)

- ths is a web forum proably read by the makers - so in some way acts as a feature requirement board - I am vocal about what I want.

 -the forum is read by potential buyers who can quickly realise whether a tool has what they need from the comments of existing users

-the forum is a forum so dont take me too serious   

-In terms of stupidity - I dont know - I think stupidity would be a gross accusation however I think they could be accused of cultural lag - The H1 was realeased at a time when MF digital backs where all tethered to a computer and operated at about 50ISO -studio tools - time has moved forward - wire free 400ISO backs mean a brave new world of portability, compact camera have face recognition AF now, the cost of microprocessing is probably 1/10th of when the H1 was concieved - roll on the H4
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Product design is, among many considerations, also a business decision. What the cost would be to develop and manufacture anyone's particular feature set in their dream camera, I have no way of knowing. If anyone can tell me what the cost would be for Hasselblad to add multi-point autofocus and how much return on the investment would be recovered and how quickly–it would be very interesting to know. Idle speculation about how viable that would be won't get us anywhere–money would. Perhaps someone with a lot of cash would like to offer to finance a prototype. I can't–sorry!

And I'm happy to agree to disagree and not take any of this too seriously. It's just a discussion about tools and technology for imaging, so I'm really not emotionally involved.

I don't have a problem with any manufacturer's decisions about their products. They make decisions based on a host of factors that I have no way of knowing about. I save my emotional energy for more important stuff. But it is fun to talk about.
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josayeruk
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« Reply #37 on: September 20, 2007, 12:51:40 PM »
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Its now on the web with more info on the softare...

http://www.hasselblad.com/promotions/h3d-ii.aspx

Jo S.x
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Dustbak
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« Reply #38 on: September 20, 2007, 01:37:36 PM »
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I see Phocus (new tool) can process 3FR files of previous generations (this also does imply 3FR files are different for the II).

That is nice. Still would like to know when the software is available, the camera is mentioned to be available right away.

Also whether it can be used with CF backs, if it carries a new firmware with added or improved capabilities as well (and which naturally).
« Last Edit: September 20, 2007, 01:39:03 PM by Dustbak » Logged
wilburdl
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« Reply #39 on: September 20, 2007, 02:27:20 PM »
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Now I don't normally reply on the MF board but I do my fair share of lurking... I must say TechTalk, you come across as disingenuous. It's almost as if your being paid by HasselBlad to take up for them. I have never seen a poster/photographer take up for a maker with as much zest as you have. Your subtle/not-so-subtle attacks on those who disagree with your idolation is bringing the level of quality discussion down a notch.
Which is rather disheartening for us peeking over the MFDB fence. I think we all want the best out of our equipment and as such take time out of our schedules to congregate on these types of forums.

That said, guys keep up the conversation, as I will now recuse myself from this particular debate.
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Darnell
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