Heliopan fader ND

[Gabe Strong]

Here's some pictures with the Heliopan Fader ND on the FS-100...

[Piotr Wozniacki]

Thanks Gabe,

What lens did you shoot with? It's strange that the upper right pic (which shows proper exposure) has such a deep DOF!

[Gabe Strong]

Ok, sorry I can't swear to anything as it was just a really quick test to
show how much the Heliopan could reduce the light in the day. First, it
was with the kit lens. Second, it was at full wide, so no help on the
shallow depth of field there either. I did set the iris to wide open (F3.5)
and then used the ND to control the exposure.....so the iris never changed
between the shots. What MIGHT be a good exercise for me to do, is set up
a shot, and expose correctly with the ND totally dialed off, and using
the iris to 'stop down' and then second, do the same shot with the iris
fully wide and use the ND to 'stop down'. That would show the DIFFERENCE
in the depth of field between having the ND filter, and not having it.
But that's just my best guess of how to do this test in a valuable way.
If you have a particular way you want me to test, just let me know, and
I'll do it and post pics for everyone. Sorry, I wasn't really thinking
too much, just was so excited that I could shoot outside without having
to use shutter speed that I don't think I did the test in a particularly
valuable way.

[Piotr Wozniacki]

OK - so it's the kit lens at the widest end, and at F3.5.

FWIW, I remember playing with the VG10 with the same lens in the local Sony Center the other day; as they didn't have any ND filter in stock, I used aperture priority (iris wide open) and auto shutter; I must say that starting with some 50% zoom and more, I was able to get quite a nice shallow DOF - even though the VG10's sensor is nothing like the FS100's one!

[Derran Rootring]

Thanks for posting these pictures Gabe.

I would also like to see a test where you adjust the exposure for the different ND settings to really see the difference in DOF. It does look like a very nice filter! Might be an even better solution then a build-in camera ND filter with only two fixed settings. Now you have a nice way to control the light.

[Gabe Strong]

Here's a quick video comparison I just stepped outside and shot.
I tried to match the exposure and shot as close as I could. However,
after each shot without the Heliopan, I had to screw the filter on,
so I had to move the camera just a little so the shots may not
match up exactly, but they are pretty close I think. Also,
sorry I didn't get it in the text, but the first shot in each
case, group is the shot with NO Heliopan filter, (high F stop
around F22) and the second shot in each group, is WITH the Heliopan
filter (Low F stop....somewhere between F 3.5 - F 6.3 depending on
if it is the wide, medium or tight shot). Anyways, here is the link.

FS-100/Heliopan depth of field tests By Gabe Strong On ExposureRoom

[Tim Polster]

Thanks for posting your test Gabe. I do not know this lens, but to my eyes the shots with the filter are soft and have a green/yellow cast added along with some vingetting to boot. Not what I was expecting from the more expensive and recommended Helipan filter.

Does the lens show this behavior without the filter in place?

[Gabe Strong]

First things first, sorry, I had accidentally hit a keyboard shortcut that
applied a custom color correction to several of the clips, as they were
selected at the time. After the color cast was pointed out to me, I went
back into FCP and checked, got rid of the CC3way filter and re uploaded it
to the same link. So if you looked at it earlier today, try it again.

Second, it's kind of hard to tell.....but because so much more of the
picture goes out of focus with the Heliopan on, it can make everything
look 'soft'. But if you look at the area that is supposed to be in
focus, I think it should look sharp still, even with the filter on.
However, when you put the filter on, and change F-stop, it seems to
change the focus point a little......which I didn't realize, and in
the attempt to keep everything equal, I did not ride focus. I will
need to look at this again and see if it really goes soft, or if I just
need to tweak the focus a little bit with the filter on to 'refocus'
on what should be in focus. There may be some vignetting at wide angles,
due to the step up ring I have between the 67mm lens and the 77mm Heliopan
filter....I thought I may have detected that, but I need to shoot against
a white piece of paper to see for sure.

[Tim Polster]

Hey Gabe,

Thanks for the update. No worries. I don't want to appear like I am pointing fingers. I watched the footage again and the color is more consistent but I still see a bit of a green cast come on when the filter shots come up.

Regarding sharpness. I am looking at the mailbox as the subject and it does go a bit soft on the filter shots. Maybe a retest using a re-focus for each shot might give a clearer impression of the filter and its impact on the image. I think the grey mailbox is a good subject for this test.

Thanks for posting as I am researching different variable NDs. Hope to see more!

[Gabe Strong]

Tim,

No problem, I have never thought about how difficult it is to do a
fair and useful test before I started doing these. For example, should
I white balance without the filter, and then white balance again after
I put the filter on? (I did NOT do that, would that be 'fair'? 'Useful
to others?) Should I refocus on the subject once I put the filter on?
I did NOT do any of these things. Maybe I should have.
I will continue testing and put some more video up later today with new
methods....

[Tim Polster]

The way I look at it is when you use the filter you would white balance and focus with it on. So I think outside in an unchanging lighting situation it would be most useful to white balance, focus and shoot without the filter. Put the filter on then white balance, focus and shoot again. On tripod being the best as well and you might as well leave the white card in the shot for reference and ease.

Thanks for your tests!

[Gabe Strong]

OK, after good suggestions from Tim, here is the latest bunch of tests.

FS-100/Heliopan depth of field tests By Gabe Strong On ExposureRoom

Take a look....

[Tim Polster]

Hey Gabe, Looks great! Thanks for shooting some more tests. The detail and color are very nice. It looks like the filter is a good addition to your kit.

The shots look very nice with less DOF in my opinion. Much better than the whole world in focus.

[Gabe Strong]

Tim,

Thanks for the input on these tests. Previously, I was just leaving all
settings identical between having the filter and not having the filter on.
But, the filter is gray and if you don't re white balance, it seems
to change the color a bit. Also, it seems you need to refocus after
putting it on. If you do these things, it seems the video you get
out of it is VERY close to the color and sharpness with no filter
on.....except there is much less depth of field, which is of course,
the point. However, I am not sure, but there might be some slight
vignetting at the wide angle, around 18mm. I hadn't thought about this
before, I bought the 77mm Heliopan to insure use on the broadest variety
of lenses, because after all, you can get step up rings pretty cheap.
But, that puts the filter out further in front of the lens, creating
more of a change of vignetting. So, if you are going to get a WIDE
lens like the 11-16, I would recommend finding the front filter thread
size, and buying a variable ND that fits it exactly, and buy the thin
version as well!

[Piotr Wozniacki]

I think Gabe has hit the nail re: potential vignetting. The lesson taken is that it's not just the filter diameter which should be at least as large as your biggest lens' diameter; it's also about the distance that step-up ring(s) will put you vari-ND filter in front of a lens!

I think that with a collection of lenses with very wide focal lengths and filter diameters range, one needs more than a single vari-ND filter...

Piotr