I'm falling deeply and madly in love ....

[Donald]

.... with the combination of my Variable and 5-stop Mor Slo Singh Ray Neutral Density filters mounted on the front of the lens.

This was at about 10 or 11 stops and was just under a 3-minute exposure (178 seconds).

The Exit from Ainster Harbour.

As always, your comments and critique are welcomed.

[IzzieK]

And I am deeply falling in love with your 50 mpx camera. This is a great image, Donald...and 3 minutes will bore me to death waiting but with results like this, simple and sharp, it will be worthwhile. How far were you from this structure? Nice to see it in lytebox, folks!

[Donald]

How far were you from this structure?

Oh Izzie, I'm hopeless at estimating distances. I've just gone to Google Earth and measured it. It tells me it was 246 yards (226 metres).

[Shadowman]

Nicely captured.

[Wavelength]

Great; at what time of the day did you capture this?

[Donald]

Great; at what time of the day did you capture this?

At 11:10am.

[george013]

I'm a bit surprised of the amount of rippling in the water after 3 minutes exposure.

George

[Donald]

I'm a bit surprised of the amount of rippling in the water after 3 minutes exposure.

Indeed. We need someone with some sort of science background to explain to us why this should be.

The same point was made about the other long exposure image I posted here recently. Maybe it's something to do with Scottish water!

[xpatUSA]

Oh Izzie, I'm hopeless at estimating distances. I've just gone to Google Earth and measured it. It tells me it was 246 yards (226 metres).

Interesting, Captain (said Spock) - the EXIF SubjectDistance tag says 24.25m (I peeked), which doesn't seem right at all. I blame Elements 11

I like the sea's texture change going from inside to outside the seawall.

[Donald]

... the EXIF SubjectDistance tag says 24.25m (Sorry, I peeked).

I know. I saw that. "Ah cannae understand it, Cap'n", said Scotty. The focus was on the lighthouse. Do the NDs throw out the readings?

[chauncey]

Dammit Donald, every time you post an image, you push me a little closer to getting one of those bodies.
Tis indeed a gorgeous picture.

[xpatUSA]

I know. I saw that. "Ah cannae understand it, Cap'n", said Scotty. The focus was on the lighthouse. Do the NDs throw out the readings?

I don't have any such filters and know little about them, sorry. Theoretically, no, would be my guess . . .

[FootLoose]

It's a beautiful image, Donald, well composed and executed. I would be tempted to remove some of those white marks on the left wall, particularly those closest to the edge of the frame.

[John 2]

I know. I saw that. "Ah cannae understand it, Cap'n", said Scotty. The focus was on the lighthouse. Do the NDs throw out the readings?

The sky looks pretty flat so I take it there were no brighter periods during the exposure time. That's the only thought I have. Very nice image.

[Donald]

The sky looks pretty flat so I take it there were no brighter periods during the exposure time. That's the only thought I have. Very nice image.

Nope, there certainly weren't, John. That was the sky from daylight to dusk today. Indeed that's been the sky for about the last week. I never remember us ever having such a prolonged period of low mist and fog as we've had in the last two weeks or so.

[Dave Humphries]

- the EXIF SubjectDistance tag says 24.25m (I peeked), which doesn't seem right at all.

OK, I have a theory on this.

Focal Length was 70mm (FF) and Aperture was f/16.

I confirm Subject Distance shows as 24.25m in EXIF.
This is going to be a 'calibrated' figure derived from 'where the cogs are' in the lens and may not bear much relationship to reality.

Also in the EXIF decoder I use (regex.info/exif.cgi), it shows calculated values for:
Depth of Field: "inf (7.08 m - inf)"
Hyperfocal Distance: "9.97 m"

I checked these on a DoF and HFD calculators independently - and they are about right.

I assume the lens would have been Auto-Focused (wide open at f/2.8) - and without the ND filter?
Then switched to manual to retain focus after the filter added?

My theory runs along the lines that if the lens was Auto-Focused, given the actual distance to subject of 225m to the lighthouse, the lens electronics (even though focusing at f/2.8), knowing the aperture that is going to be used (giving such a wide Depth of Field), decided that 24m was a good compromise - or maybe it ain't that clever, because the HFD calculator shows that 27m is the HFD for f/5.6.

Assuming the camera and lens are clever; knowing the aperture and focal length, and for all we know, containing an electronic HFD table, possibly knew this before even looking through the lens and attempting to focus, so it only had to settle on a lens focus distance somewhere between 7m and infinity, in this case it chose 24m. I suspect if you continually refocused and took shots, due to tolerances of optics, atmospherics, mechanics and electronics, you might end up with a variety of values between say, 10m and 50m.

Obviously, if Donald manually focused, all bets are off and the 'calibrated' figure derived from 'where the cogs are in the lens' is going to be wherever his eyes thought it looked sharpest, plus also perhaps deliberately 'backing off infinity' a bit for HFD. Well, that's what I do sometimes.

If Donald used AF with the filter on, then it accidentally chose a safe figure, since it couldn't have used optical information.

I'm sure there are some gaping holes in my theory and logic, but there you go - it's getting late.

Cheers, Dave

[Donald]

OK, I have a theory on this.

Not sure I understand it all, but the gist of it makes sense.

Focusing was automatic before the filters were screwed on. I am certain of this because I remember me telling myself very clearly, "Do NOT touch the focusing ring".

[Dave Humphries]

I'm a bit surprised of the amount of rippling in the water after 3 minutes exposure.

Oh, I got a theory on this too

I wonder whether, due to distances between physical parts of jetty, shore, underwater landscape features, et al - wave period and wave speed, there is a predominance of swell or dips at certain places across the harbour, I think I mean like 'standing waves'.

Discuss

Cheers, Dave

[Dave Humphries]

Not sure I understand it all

Thee and me both

[Donald]

Oh, I got a theory on this too

I wonder whether, due to distances between physical parts of jetty, shore, underwater landscape features, et al - wave period and wave speed, there is a predominance of swell or dips at certain places across the harbour, I think I mean like 'standing waves'.

You have worded it better than I could have, but that was my own thought on the matter.