[GreatFrog]

I was using a polariser and medium 0.6 filter on the 28 - 45...but only on nr. 3

.6 stops ND?

[abruzzi]

.6 stops ND?

.6 is usually 2 stops (I've never understood the different naming schemes of ND filters...)

[ivanvernon]

Sunrise over our garden pond, grandeloquently dubbed Mystic Pond. Purpose of composition: An effort to demonstrate that the P67-105/2.4 is not just for portraiture.

KIT: Pentax 645Z with (adapted) Pentax 67 105 f2.4.

[kaseki]

.6 is usually 2 stops (I've never understood the different naming schemes of ND filters...)

ND = - log (base 10) of the relative transmission. Hence, ND 1 transmits 10%.
stops = multiplicative factors of the square root of 2 in aperture diameter, or 2 in aperture area. So two stops = a factor of 4, and the log of 1/4 is -0.6. A 0.6 ND is thus a factor of 4 reduction in transmission (transmission is 25%).

[tuco]

.6 is usually 2 stops (I've never understood the different naming schemes of ND filters...)

Here is another take on the subject. ND filters can be listed by their transmission density or Filter Factor just to keep us confused.

For our purpose 0.3 of transmission density = 1 stop. So a ND filter listed as 0.6 density = 2 stops, 0.9 = 3 stops, etc. But many ND filters are listed by their filter factor. For example, a NDX4, NDX8 and NDX400 have a filter factor of 4, 8 and 400. And to calculate stops from a given filter factor, Wikipedia gives us the following Filter Factor formula:

Code:

 Filter Factor = 2X     Where X = stops

NDX4 and NDX8 are pretty easy to do in your head:

Filter Factor of 4 = 22
Filter Factor of 8 = 23

But what about a NDX400 with a filter factor of 400? That's not so easy to do in your head and Wikipedia falls short of helping us out there. You have to solve for X on your own. You can do that using log base 10 or the Natural Log (ln) that should be on most calculators that also have a log key. With FF = Filter Factor and using the Natural Log, ln:

FF = 2X
ln(FF) = ln(2X) = X ln(2)

X = ln(FF)/ln(2)

With FF = 400

X = ln(400)/ln(2) ≈ 8.64 or say 9 stops

[abruzzi]

heh. I do undertand that the different things mean something, I just wonder how useful those meanings are to the users, who are probably metering, thinking "i need to darken the sky by about two stops to get it closer to the ground" or "my film only has 5 stops of range and my scene has 7"

[tuco]

heh. I do undertand that the different things mean something, I just wonder how useful those meanings are to the users, who are probably metering, thinking "i need to darken the sky by about two stops to get it closer to the ground" or "my film only has 5 stops of range and my scene has 7"

Okay, I though it was the naming convention of ND filters that was confusing.

[Ed Hurst]

Stunning mate. Nothing but greyness at the NSW/QLD border at the so called Sunshine Gold Coast - am picking up a hire car tomorrow...

---------- Post added 05-08-18 at 02:40 AM ----------

More from Melbourne...

Z and DA 28 - 45

Thanks, Paul - and lovely Melbourne shots! You'd never guess the punting one is Australia...

[itshimitis]

Thanks, Paul - and lovely Melbourne shots! You'd never guess the punting one is Australia...

Have my hire car will travel...Probably heading south towards Byron Bay today...

[Ed Hurst]

Here's the Milky Way version of Horse Head Rock

645Z with 25mm f4 DA (pano)

[IMG][/IMG]

[GreatFrog]

Here's the Milky Way version of Horse Head Rock

645Z with 25mm f4 DA (pano)

[/url][/IMG]

amazing photo Ed. Reminds me of the analogous Horse Head nebula...very other-worldly. Can you tell us how you created this shot?

[sculptormic]

Pourville-sur-Mer

Pentax 645Z DA 28-45

[Ed Hurst]

amazing photo Ed. Reminds me of the analogous Horse Head nebula...very other-worldly. Can you tell us how you created this shot?

Thank you so much, GreatFrog. Your feedback and interest mean a lot to me.

Let me try and tell the story a little...

The first thing is that I am very much in love with the Milky Way, but realised a little while ago that simply shooting it alone doesn't express what I feel - and rapidly gets boring. What I want is to find amazing places that are beautiful and somehow other-worldly to set against the Milky Way. Australia is rich in such places, and I keep having adventures finding and capturing them... From well-known places like Uluru (Ayer's Rock) to the Australia Telescope Compact Array and stunning, lesser known spots.

So the story of this picture began with exploring the country to find a place that inspired me. Horse Head Rock is a great example of that.

In terms of the actual shooting itself, it was a real mix of practical and aesthetic considerations. On the practical front, these are some of the factors I had to bear in mind:

1. Getting a very clear night (obviously). The weather was not perfect, but I gambled and did the 12 hour round trip drive anyway (actually my good friend Ivan did the driving on this particular trip!). As we approached the location, there were clouds and also some smoke from back-burning fires which threatened to ruin it, but it all cleared when it mattered.
2. You need the time of year when the Milky Way core is rising in darkness. That immediately cuts down the part of the year that's possible.
3. Moon needs to co-operate - either you need a moon phase that casts very little light or you need to time it such that the moon is not up at all when shooting. In this case, we did the latter - timing things so that the core rise occurred before moon rise.
4. Tides. This is the hardest and most dangerous issue with this shot. The position is not accessible at high tide - you would get dangerously cut off, so it's necessary to find a day when tide, weather, moon and core rise all line up.
5. Light pollution in background from some angles. This is annoying. You want to stand to the left to hide the light behind the rock, but that puts the Milky Way in the wrong place for the composition and also gets the main rock mixed up with the cliff. As with so many things, this is a trade-off.
6. I wanted foreground water for interest, which meant I couldn't tackle point 4. by going in at low tide for safety. Another trade-off!
7. Although it's an obscure spot, other people do show up there. Within the narrow window of opportunity with the points above, you have to hope no one else is around making light, because if you wait until they stop, the window is lost.

So it took A LOT of planning. A spreadsheet with all the factors listed, with possible dates highlighted. I feel amazed that the issues aligned because I am about to leave Australia, so didn't have lots of chances to wait for obvious perfection. I had to seize a day when it seemed just about possible (tide was a bit high, cloud was possible, I would have preferred a little moon than no moon) - but accepted that and hoped.

VERY satisfying that it worked out!

Hope that tells you what you wanted to know about the story of the shot. I will go back there and try to get it with more waves and subtly moonlit foreground scene. But this version will keep me happy for now!

Thanks again for your interest in the picture, my friend.

Ed

[dsmithhfx]

I was using a polariser and medium 0.6 filter on the 28 - 45...but only on nr. 3

I was thinking more something in pp, like hdr with saturation on "11", if you get my drift.

[GreatFrog]

Thank you so much, GreatFrog. Your feedback and interest mean a lot to me.

Let me try and tell the story a little...

The first thing is that I am very much in love with the Milky Way, but realised a little while ago that simply shooting it alone doesn't express what I feel - and rapidly gets boring. What I want is to find amazing places that are beautiful and somehow other-worldly to set against the Milky Way. Australia is rich in such places, and I keep having adventures finding and capturing them... From well-known places like Uluru (Ayer's Rock) to the Australia Telescope Compact Array and stunning, lesser known spots.

So the story of this picture began with exploring the country to find a place that inspired me. Horse Head Rock is a great example of that.

In terms of the actual shooting itself, it was a real mix of practical and aesthetic considerations. On the practical front, these are some of the factors I had to bear in mind:

1. Getting a very clear night (obviously). The weather was not perfect, but I gambled and did the 12 hour round trip drive anyway (actually my good friend Ivan did the driving on this particular trip!). As we approached the location, there were clouds and also some smoke from back-burning fires which threatened to ruin it, but it all cleared when it mattered.
2. You need the time of year when the Milky Way core is rising in darkness. That immediately cuts down the part of the year that's possible.
3. Moon needs to co-operate - either you need a moon phase that casts very little light or you need to time it such that the moon is not up at all when shooting. In this case, we did the latter - timing things so that the core rise occurred before moon rise.
4. Tides. This is the hardest and most dangerous issue with this shot. The position is not accessible at high tide - you would get dangerously cut off, so it's necessary to find a day when tide, weather, moon and core rise all line up.
5. Light pollution in background from some angles. This is annoying. You want to stand to the left to hide the light behind the rock, but that puts the Milky Way in the wrong place for the composition and also gets the main rock mixed up with the cliff. As with so many things, this is a trade-off.
6. I wanted foreground water for interest, which meant I couldn't tackle point 4. by going in at low tide for safety. Another trade-off!
7. Although it's an obscure spot, other people do show up there. Within the narrow window of opportunity with the points above, you have to hope no one else is around making light, because if you wait until they stop, the window is lost.

So it took A LOT of planning. A spreadsheet with all the factors listed, with possible dates highlighted. I feel amazed that the issues aligned because I am about to leave Australia, so didn't have lots of chances to wait for obvious perfection. I had to seize a day when it seemed just about possible (tide was a bit high, cloud was possible, I would have preferred a little moon than no moon) - but accepted that and hoped.

VERY satisfying that it worked out!

Hope that tells you what you wanted to know about the story of the shot. I will go back there and try to get it with more waves and subtly moonlit foreground scene. But this version will keep me happy for now!

Thanks again for your interest in the picture, my friend.

Ed

That is amazing Ed. Well planned and well-executed. It is an amazing shot, one of my favorites.