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Topic: Light loss through Panasonic ultra short throw lens?
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Joined: Nov 22, 2019
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I'm looking for technical data about the light loss through the ET-DLE030 lens. The documentation says that it's an F2.0 but it uses a mirror. My knowledge about projection through mirrors tells me that a significant amount of light is lost when shooting a mirror. F2 is comparable to other lenses in the Panasonic line without mirrors. Panasonic North America tells me that they don't have any more information about this. So, I'm looking to the wide open internet...

Does anyone have any info, quantifiable or anecdotal, about the brightness of an image with the Panasonic ultra short throw single DLP lenses?

(ET-DLE030, ET-DLE-035)
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I'm not sure if there is any room for Panasonic to be incorrect in their specifications. If this lens is rated as a f2.0 lens, then it likely would open them up to a lawsuit if it didn't perform as such, or at least within a 10-20% tolerance thereof.

I would trust the documentation.

Unfortunately, as a very expensive lens, this is not one which I have personally had a chance to play with, and if I did, I'm not sure I would do meter readings on it to compare it with other models.

Depending on the setup you are trying to achieve, and image size, I would be reaching out to Panasonic. But, if you intend to buy entirely off the used market, they may not be of much use. I'm quite sure the people you would work with would be engineers who are working off their published specification no matter what.

Once again, as such, I would expect that published specification to be fairly accurate.
AV Integrated - Theater, whole house audio, and technology consultation during the build and installation process in the Washington, DC metropolitan area.
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Here's a quote of what Panasonic said:
"There aren’t any specifications available related to any light lost with optional lenses. The light specifications of a projector is based on its use with a standard lens following industry standards for measuring brightness. Brightness specifications are not available for optional lens models."

I HAVE used these lenses in a rental capacity but have never been able to compare one lens type to another in the same room/screen. They generally look pretty good but I've mostly only seen them on smaller screens (7k projector on a 6'x10' screen or so). Querying other techs about this question has yielded mixed responses. Some say they don't think there is too much difference compared to a non-mirror lens and others say that there is a significant decrease in brightness.

I don't doubt Panasonic's specs. But based on the response from Panasonic support and my own ignorance of optics, it's not clear to me if there is another brightness/light loss factor involved beyond the basic F spec of the lens.

Using the projection calculator here on Projector Central, I've found that I can't make any other lens any brighter than the DLE030 on a given size screen and most of them are dimmer, even at the brightest zoom position.
[Edited by chmedly on Nov 26, 2019 at 1:51 PM]
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f1.8 and f2.0 are very similar in terms of how much light goes through. Most people can't visibly see a difference between the two in terms of brightness.

I would expect that it is similarly bright across most of their lenses and you can get similar results.

In most cases, brighter is better.
AV Integrated - Theater, whole house audio, and technology consultation during the build and installation process in the Washington, DC metropolitan area.
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chmedly, I am about to purchase an unreturnable ET-DLE030 and had the same exact question. Did you end up buying one and if so, did you (or anyone else in this forum) experience any noticeable light loss?