FYI, the HC1 lens hood, when attached to the camera normally allows the attachment inside the hood, of a 37mm screw in filter.

Also, the chart of exposures for the HC1 that I found is incorrect. It has an extra f4 at 0db gain and is missing the f/9.6.

I just ran the manual exposure test for my HC1 and it is:

f/stop---db gain
1.8------18
1.8------15
1.8------12
1.8-------9
1.8-------6
1.8-------3
1.8-------0
2.0-------0
2.4-------0
2.8-------0
3.4-------0
4.0-------0
4.0-------0
4.0-------0
4.0-------0
4.0-------0
4.0-------0
4.0-------0
4.8-------0
5.6-------0
6.8-------0
8.0-------0
9.6-------0
close-----0

Cheers, Duane

Could you run the same test with the lens fully zoomed in? You should get f/2.1 instead of f/1.8, I wonder will the other values stay the same. Thanks!

My understanding is that at f/4.0 the camera uses built-in ND filters to decrease exposure, thus multiple exposure steps for the same aperture. Is that right?

Also, I presume that when you switch from auto to manual, the exposure slider does not start from the middle, it starts from the position that corresponds to currently chosen automatic setting, right?

I am currently bidding on a used HC1 on ebay, so the more I know about the camera the better. I've read that one has to do the "tabectomy" to ensure that a screw-in filter works with the stock hood. Unless you mean something like this:

http://www.dvinfo.net/gallery/files/...8/Screw-on.jpg

I saw an HC1 on ebay with non-stock and non-A1U hood. Maybe it was large PDX10 hood? I don't know.

Yes. But it will also use a larger bit range when it has enough light because it has 14-bit dsp. So when there is too much light it will just compress it to the picture resulting in a better image than just using nd's. That's one of the reasons hc1 looks so good in good lighting.

When the lever is at 6 stops from the right the iris is fully open. But then you do need to use nd-filters.

Yes, at the long end the max aperture is 2.1. Which is actually pretty fast compared to for example the hc3.

Yes, hc1 uses internal nd-filters which you cannot control yourself. The cmos sensors is also very good in bright lighting conditions and the 14-bit dsp will use the extra range to compress lighting. That's why you can close down the exposure and sometimes it doesn't use nd's or close the iris but still the brightness goes down. That's the dsp doing its work. The HC1 tries to use F4 as much as it can as the lens is best in that aperture.

I have run this test at telephoto settings and you are shooting at f/2.1 but the information shown when played back still shows as f/1.8. Probably due to the simplicity of the aperture design.

Yes, that is correct. When I set the camera to telephoto and look inside the lens, you can there are no changes through the first 6 steps of exposure, when the gain setting is changing. You can then see the changes in the aperture until it reaches f/4, it stays at f/4 as you continue to adjust the exposure with the neutral density filter sliding in from the bottom. After it is fully implemented the f-stop starts to stop down.

I've never check this, sorry.

That is exactly how a filter is installed.

Duane

In my tests, I can see the neutral density filter move with each setting of the exposure lever. Can you post a link to any documentation concerning this electronic adjustment of the cmos sensor that adjusts exposure?

Thanks,
Duane

http://digitalcontentproducer.com/hd...ing_down_cmos/

http://geekswithblogs.net/lorint/arc.../23/64031.aspx

Mikko,

Thanks for the links to your sources but I have to conclude from my research, using this camera and observation of the aperture mechanism I described earlier, that these two sources are incorrect.

It is widely believed, and I concur, that this camera has a built in neutral density filter and does not use electronic adjustments of the cmos chip as a exposure adjustment (except the black stretch available on the A1U).

This earlier thread - http://www.dvinfo.net/conf/showthread.php?t=60555 - which on the last page includes a link to a patent description showing the aperture/neutral density assembly, has confirmed for me that there is a built in neutral density filter. One poster notes that the service manual describes the neutral density filter in a schematic of the lens.

Cheers,
Duane

Sorry for coming back to this old thread, but how can those ND filters work when the aperture doesn't change for eight times staying at F4 even when "dropping down"? Surely it has to use some sort of EIP.

It's the neutral density filters which keep the aperature a F4. The table below is just my estimate.

Sony HVR-A1U Exposure Chart

Exposure---Aperture---NDx---Gain
----1-------Closed-----7-----0
----2-------8.0--------7-----0
----3-------6.8--------7-----0
----4-------5.6--------7-----0
----5-------4.8--------7-----0
----6-------4.0--------7-----0
----7-------4.0--------6-----0
----8-------4.0--------5-----0
----9-------4.0--------4-----0
---10-------4.0--------3-----0
---11-------4.0--------2-----0
---12-------4.0--------1-----0
---13-------4.0--------------0
---14-------3.4--------------0
---15-------2.8--------------0
---16-------2.4--------------0
---17-------2.0--------------0
---18-------1.8--------------0
---19-------1.8--------------3
---20-------1.8--------------6
---21-------1.8--------------9
---22-------1.8-------------12
---23-------1.8-------------15
---24-------1.8-------------18