Do I have to have an A lens - AVS Forum
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post #1 of 19 Old 12-28-2012, 06:07 PM - Thread Starter
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New here and learning about the world of projectors. I just order my first ever for a dedicated theater room. I purchased a JVC 4810 and now I am doing the research on a screen. I watch mostly movies and thus want a 2.35 screen. However, I see that the majority of folks who have a 2.35 screen also have A lens. I was not anticipating spending the money needed for A lens.

What are the drawbacks to simply using zoom? Do I need the A lens or should I stick with a 16:9 screen?

Thanks in advance.
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post #2 of 19 Old 12-29-2012, 03:58 AM
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You can use the zoom provided it has the range range (a zoom ratio in excess of 1.33), and a lot of people do. Unless you do a comparison, you'll probably find you're more than happy with the image too.

The only problem you may notice is that when you zoom, the black bars above and below will move off of the screen and onto the wall above and below the screen. If the wall is light coloured you may notice it in some scenes. If you sit very close you may notice the pixels enlarge but you can test this by using your existing screen (ignore the image spilling over the sides and just see what you think of the image on the screen).

Either way, I would go for a scope screen that is the same height as your current 16:9 screen. Scope movies were designed to be the same height, only wider than 16:9, so that alone is a step in the right direction. smile.gif

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post #3 of 19 Old 12-29-2012, 04:30 AM
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At least you have the lens memory in the RS4810 to help: I have the X35 and use the lens memory for 1.85:1 use when I take my lens away to make a small adjustment. I find it is very consistent, so no need to fiddle about making further adjustments for each film. Of course as Gary says, if you try a (good) lens then you might find you can't go back to zooming: I tried recently to see if I could simplify my set up by getting rid of my lens and just using the lens memory, but I found that the image just lacked something that I missed. However, zooming will certainly get you started. The other reason for me is that I can't get rid of my lens as Gary knows where I live. wink.gifbiggrin.gif

Zooming: Been there, done that, bought the lens...
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post #4 of 19 Old 12-29-2012, 04:42 AM
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Quote:
Originally Posted by Kelvin1965S View Post

The other reason for me is that I can't get rid of my lens as Gary knows where I live. wink.gifbiggrin.gif

It has been said that I am pro lens. smile.gif

Gary

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Who says Cameron is "right" and why do we care about him so much - lol!

I trust Gary Lightfoot more than James Cameron.
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post #5 of 19 Old 12-29-2012, 04:53 AM
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Ahh!! He's stalking me. wink.gif I haven't sold it honest Gary, I was using it only last night. biggrin.gif

Zooming: Been there, done that, bought the lens...
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post #6 of 19 Old 12-29-2012, 05:03 AM
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yes, I know.

I also know what else you did last night... wink.gif

Gary

Quote:
Originally Posted by elmalloc
Who says Cameron is "right" and why do we care about him so much - lol!

I trust Gary Lightfoot more than James Cameron.
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post #7 of 19 Old 12-29-2012, 08:10 AM - Thread Starter
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Quote:
Originally Posted by Gary Lightfoot View Post

You can use the zoom provided it has the range range (a zoom ratio in excess of 1.33), and a lot of people do. Unless you do a comparison, you'll probably find you're more than happy with the image too.
The only problem you may notice is that when you zoom, the black bars above and below will move off of the screen and onto the wall above and below the screen. If the wall is light coloured you may notice it in some scenes. If you sit very close you may notice the pixels enlarge but you can test this by using your existing screen (ignore the image spilling over the sides and just see what you think of the image on the screen).
Either way, I would go for a scope screen that is the same height as your current 16:9 screen. Scope movies were designed to be the same height, only wider than 16:9, so that alone is a step in the right direction. smile.gif
Gary

Ok that is what I thought. As this is my first projector, and it is a solid projector at that, I feel that I should just settle on zoom for the time being. Once the wife gives me clearance to spend a bit more on our system then A lens might be in the cards. Until then I will settle on the zoom method.

In regards to the black bars showing outside of the screen, will painting the wall behind the screen black be of any benefit? I was thinking I might need to invest in velvet or something if paint wasn't enough. The room is completely light controlled and all the walls are carpet are dark brown. I could probably get the ok to paint the screen wall but only if it is going to help.
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post #8 of 19 Old 12-29-2012, 08:28 AM
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Having the screen wall black should help (I used black carpet). When I zoomed, I usually only saw the black bars during dark scenes anyway.

Gary

Quote:
Originally Posted by elmalloc
Who says Cameron is "right" and why do we care about him so much - lol!

I trust Gary Lightfoot more than James Cameron.
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post #9 of 19 Old 01-04-2013, 01:02 PM
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I just got my new 2.35 screen up and love it. I won't be able to go back to 16.9 screen. I have the RS66 and was surprised at how much FL I lost zooming. On 16.9 viewing I was at 12fl but when zoomed to 2.35 it fell to 7fl. I was not expecting that... It makes sense I just did not think about it. For reference my throw is about 16ft and screen is 138"
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post #10 of 19 Old 01-04-2013, 01:16 PM
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Can you not just open the iris some more for your 2.35:1 setting, this is what I do. Despite having a lens I still need to balance the fL for both aspects, so my 16:9 is minimum iris and my 2.35:1 I open the iris 4-5 clicks. Both aspects measure 102 Lux which is about 15fL on my 1.5 gain screen.

Zooming: Been there, done that, bought the lens...
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post #11 of 19 Old 01-04-2013, 01:25 PM
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Yes and that is what I did. I have not had the chance to really play around with the setup yet. At 16.9 (110") I was on low lamp and -11 on the iris. With the 2.35 (138") I went to high lamp with -9 iris. With those settings at 16.9 I'm at about 90lux (12.5 fl) and 2.35 I was at about 87lux (12.1 fl)

The fan noise was a little to loud for me though. So I will play more with the iris and try and keep on low lamp. I was just worried what it would to to the contrast ratio by having the iris at 0
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post #12 of 19 Old 01-04-2013, 01:30 PM
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I see what you mean. When I saw the X55 demo it was at full zoom and initially the iris was fully open and I wasn't that impressed with the black level. My X35 set up is minimum zoom and (for 16:9 anyway) minimum zoom and the blacks look much better for it even though my room isn't as black as the room it was demo'd.

Zooming: Been there, done that, bought the lens...
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post #13 of 19 Old 01-05-2013, 10:44 PM
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I will chime in on the 'do I need an A Lens' question as I just got an A Lens and I just got a 4810.

If you haven't seen that projector with an A Lens you will be thrilled with the picture and won't be able to imagine a nicer picture. If an A Lens happens to fall in front of it and you see the benefits of a brighter picture and denser pixel structure (yes, even with the e shift!) you will have a hard time going back to zooming. wink.gif
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post #14 of 19 Old 01-06-2013, 07:06 AM
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What A Lens did you go with?
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post #15 of 19 Old 01-06-2013, 02:10 PM
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Panamorph 480
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post #16 of 19 Old 01-11-2013, 08:09 AM
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I m also in the same boat as the TS. I have a JVC X35 and have the opportunity to buy a HD5000 Prismasonic + Prismasonic Curved Screen lens for a good price. But what are the pros/cons of using a curved screen when using A-lens. And what are the pros/cons of using a curved screen when NOT using A-lens? (I can also buy the curved screen only for a good price)
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post #17 of 19 Old 01-11-2013, 08:30 AM
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The pros to using a curved screen with an A lens is that you can set the curve to compensate for the pincushion caused by the lens. If you have a long throw set up then the pincushion becomes very small, so you need to consider this.

The con of using a curved screen without a lens (and this includes sliding the lens out of the way for 16:9 content) is that the image will overspill the middle top and bottom of the screen so it will look a bit like a barrel laid on it's side if you follow? There is no benefit to using a curved screen without a lens apart from arguably that it looks cool and might not direct as much light to the side walls as a flat screen would if the room is less than ideal. However, if you can accommodate a fixed curved screen, then I guess that it is a dedicated room and therefore should have black side walls and ceiling at least near the screen.

If you have a lens and curved screen, then you will have to leave the lens in place the whole time so it is compromising 16:9 viewing as this will be scaled down to 1400 x 1080 (approx). Therefore I think that it's a better solution to have a long throw set up with minimal pincushion to start with and then use a flat screen (or at least the curved screen could be so slight that 16:9 content could be viewed without the lens in place.

Zooming: Been there, done that, bought the lens...
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post #18 of 19 Old 01-11-2013, 11:34 AM
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How can I test the 2:35:1 zooming on my JVC X35? When I choose Anamorph A or B the ratio is wrong. ZOOM (in the setting 4:3, 16:9 or ZOOM) is grayed out and cannot be selected.
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post #19 of 19 Old 01-11-2013, 01:26 PM
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Sander, you don't use the anamorph button to select 2.35:1 unless you have an anamorphic lens. You need to set the anamorph button to 'Off'. The only way you can do it is by setting up the lens memory and zoom to fill your 2.35:1 screen (focus and shift accordingly) and save this setting, call it something like 235 or whatever you like to make it easy to find. Then zoom smaller with 16:9 content until the image fits heightwise on your 2.35:1 screen (with side bars) and save this in the lens memory as 16:9 (or whatever).

Zooming: Been there, done that, bought the lens...
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