| Author |
Message |
perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
|
| Posted: Sat Apr 05, 2008 5:25 pm Post subject: HD144 vs. HD145 |
|
|
I've got my eye on a set of clear HD145s that I'd put my own filter elements in. They appear to have the same mounts as the HD8bs that came with my 808s, but I'm not certain from the pic.
So, two questions - will 145s mount directly on an 808, and if so, are they as sharp as 144s? I'm pretty sure that they won't fit without an adapter (too costly to buy; too much time to make myself), but it's worth a shot.
_________________
|
|
| Back to top |
|
 |
chillman
Joined: 09 Apr 2007
Posts: 134
Location: Germany, Bavaria
|
| Posted: Sat Apr 05, 2008 6:11 pm Post subject: |
|
|
|
No they will not fit directly of course, that's the reason why there are adapters for it.
|
|
| Back to top |
|
|
kschmit2
Joined: 09 Mar 2006
Posts: 1141
Location: Heidelberg, Germany
|
| Posted: Sat Apr 05, 2008 9:31 pm Post subject: |
|
|
sharpness between 144 and 145 lenses is virtually identical.
Throw distance is 1.33x screen width for the 144s, 1.4x for 145s
Kai
|
|
| Back to top |
|
|
perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
|
| Posted: Sun Apr 06, 2008 3:15 am Post subject: |
|
|
Hope springs eternal.  Still, at the right price they might make sense, since I can do the color filtering myself. I can always come up with adapters later if it's attractive enough...
Is there a significant sharpness upgrade vs. HD8bs or (which I'm using now) PT65s, which I understand are somewhat sharper than HD8s? I would presume there is, or else HD144/145s wouldn't be such a big deal, but I'm still a relative n00b, so...
I can always filter the PT65s I've got, which are not in perfect shape but I doubt the issues are really hurting PQ (a single scratch on one lens, not enough to affect focus or contrast significantly). So unless the 145s are noticeably better, it's not necessarily worth the effort/cost to adapt and color filter...
_________________
|
|
| Back to top |
|
|
Tom.W
Joined: 09 Mar 2006
Posts: 6635
|
| Posted: Sun Apr 06, 2008 3:45 am Post subject: |
|
|
|
What color filters are you planning on using ?
|
|
| Back to top |
|
|
Mark_A_W
Joined: 15 Mar 2006
Posts: 3068
Location: Sunny Melbourne Australia
|
| Posted: Sun Apr 06, 2008 10:21 am Post subject: |
|
|
There's no point getting clear 145s.
Any sharpness advantage over HD-8's will be negated by adding DIY filters (YUCK!!!).
|
|
| Back to top |
|
|
perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
|
| Posted: Sun Apr 06, 2008 12:42 pm Post subject: |
|
|
These filters.
Mark, these aren't gels slapped on the face of the CRTs. The colors are so dead-on that I imagine these were made specifically for filtering CRT lenses. The plan is to add them as a rear element to the new lenses, or replace a flat rear element if there is one. That shouldn't result in the backreflections and loss of sharpness you get using gels or other DIY methods. At least, that's what I think.
Honestly, for the moment, it hardly matters as I'm not running HD yet. But at some point, I will be. Semper preparus, and all that. And in that case it's better to already have good lenses...
_________________
|
|
| Back to top |
|
|
Mark_A_W
Joined: 15 Mar 2006
Posts: 3068
Location: Sunny Melbourne Australia
|
| Posted: Sun Apr 06, 2008 12:47 pm Post subject: |
|
|
The rear of the lens is curved.
There's no way you can fit the filtered flat section inside the lens, and there's no space between the tube and the lens.
I hope I'm wrong but....
|
|
| Back to top |
|
|
perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
|
| Posted: Sun Apr 06, 2008 12:58 pm Post subject: |
|
|
| Mark_A_W wrote: | The rear of the lens is curved.
There's no way you can fit the filtered flat section inside the lens, and there's no space between the tube and the lens.
I hope I'm wrong but.... |
If I have to, I can machine small clip mounts to add it as a flat element. The other option is to make them part of the adapters, as I'd have to make those. Although, if what you're saying is true about the lens going right to the tube face, yes, I would be hosed.
I thought it might have a flat rear element, as the PT65s do. If I don't get the 145s, I'll probably mod the PT65s that way. But based on what you're saying, I don't think I'll be willing to pay a lot for them!
_________________
|
|
| Back to top |
|
|
front_range
Joined: 03 Mar 2008
Posts: 64
Location: North of Colorado Springs
|
| Posted: Sun Apr 06, 2008 1:27 pm Post subject: |
|
|
|
The rear element in the 145 is slightly convex, but it only becomes even with the back of the lens assembly if the corner focus is adjusted all the way in to it's rear-ward position. Even then you sill have whatever Scheimpflug hardware is installed in between the tube face and the back of the lens assembly which puts a pretty wide air gap between the lens and tube. I have a 708 on the bench now sans lenses. The tube face is at least 5/8" behind the back element of the 145's at the minimum focus point. So you could put the element inside the Scheimpflug spacer on top of the tube face (I'd think)
|
|
| Back to top |
|
|
perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
|
| Posted: Sun Apr 06, 2008 1:56 pm Post subject: |
|
|
I'll have to take a look. Unfortunately without an actual HD145 it's kind of hard to know...
_________________
|
|
| Back to top |
|
|
front_range
Joined: 03 Mar 2008
Posts: 64
Location: North of Colorado Springs
|
| Posted: Sun Apr 06, 2008 2:12 pm Post subject: |
|
|
|
If you want something to play with, buy a cheap set of TAC3's. The mount is the same as the 145. They are all plastic, so they are cheap to ship, and they are virtually worthless.
|
|
| Back to top |
|
|
perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
|
| Posted: Sun Apr 06, 2008 2:25 pm Post subject: |
|
|
| front_range wrote: | | If you want something to play with, buy a cheap set of TAC3's. The mount is the same as the 145. They are all plastic, so they are cheap to ship, and they are virtually worthless. |
I might actually have some of those... *checks*
Yep, I've got a set on this BV600. Heh. Any idea if the arrangement of the rear elements is similar?
_________________
|
|
| Back to top |
|
|
front_range
Joined: 03 Mar 2008
Posts: 64
Location: North of Colorado Springs
|
| Posted: Sun Apr 06, 2008 2:39 pm Post subject: |
|
|
Sorry, that I can't tell you since I haven't studied a TAC for longer than it took to toss it in the trash. If there is any similarity, it's pure coincidence. It will give you an idea how to make an adapter, but you'll need to look behind your current lenses and see if you can fit the filter on the tube face inside your flapping setup.
Like I said, with the focus set all the way in on the 145, the element is flush with the base of the lens mounting ring. The offset for the TAC3's mounting tabs relitive to the back of the lens mounting ring is identical to the 145. I got a pair of the two mounts here and just checked them again. All the dimensions you need for the 145 can be found from the TAC3 base.
|
|
| Back to top |
|
|
|
|
