Monday, 13 July 2020

13.07.2020 More laketime digiscoping practice.

~~

Monday 13th bright overcast with a few brighter periods. Cycled to the lake again.

Set up beside the [private] picnic table so that I could sit down behind the telescope and camera. I had left my new stool behind but still didn't want to present a standing profile on the bank. I am almost sure that the birds keep their distance. Few ever come within 50 yards while I am there.

I was quite pleased with this action shot despite it not being very sharp. One gull bullied another off the nesting box. It makes for quite a dramatic image.

The Grebes were sulking around the far shore at 125 yards or more. One of the birds had at least three young snuggled into its back. While the other fished almost constantly underwater. The background was far too dark and busy without any chance to put it out of focus at that distance. The image below was taken when the "fishing" bird popped up accidentally at about 60 yards away. It dived again almost immediately.

Unexpectedly, there were a few gulls present for the first time. The nearest at about 100 yards and spread out beyond that to probably about 140 yards or more. With lots more gulls arriving steadily and only a few leaving in the hour and half I was there. I decided to practice focusing on the gulls since they were so bright and provided excellent contrast to their edges in the viewfinder.

Sadly most of these images, which I saw as razor sharp in the G9 viewfinder, were slightly out of focus. Or just plain soft. I was using the 2-step wireless shutter release. So assumed that it was a focusing problem rather than camera shake. Naturally this was very disappointing and needs much more thought.

If it really was a focus problem then a whole bunch of birds, scattered over so many yards of water, should have at least some of them in sharp focus. If it was a depth of field problem then the same rule applies. I could see the [camera applied] blue rims as a guide around the birds while using manual focus.

Sudden resurfacing of fishing grebe at 60 yards.

In the viewfinder I could easily see the finest detail. I just didn't capture it despite being very careful about touching the telescope or camera. The G9 was adjusted to shutter priority and 1000 ISO to achieve 1/500 exposures. The problem is that the camera can't read the telescope's focal length or F number in manual focus. There are no contacts so manual focus is the only option.

The test of image sharpness is usually seeing fine detail in the bird's plumage. A bird's eyes are also a good test. They give the bird its identity and character. I could see all of this clearly in the viewfinder but not in my images. The obvious question is: Why?

I had the set-up nicely balanced. The Sirui gimbal head was too free moving for my taste. Easily adjusted in tilt but not in panning. Though my repeated "exercising" of the internal and highly eccentric gearwheel had resulted in a much softer lock with more useful friction. Sadly it was still not ideal with such a long focal length.

Yet again I was delighted by the brightness and sharpness of the view through the Kowa '884 telescope visually. If only I could capture what it presents to the camera. This is something I can research further and practice at home. If I can arrange a long enough, clear line of sight. At present I can only manage about 50-60 yards. Whereas the birds on the lake are often twice that distance.

EDIT: I have just had a thought. Some photographers suggest that IS [image stabilisation] be switched off when using a tripod. The theory being that IS is designed for handheld situations. Which means only certain low frequencies need be neutralized. Some users claim that IS spoils the images from tripod mounted cameras by adding unwanted vibration. This needs further testing if I am to progress.  

Another safe landing chalked up to nature's autopilot. Probably just over 100 yards away.

It is all too easy to forget exactly how far the birds are away from my fixed position. There being no obvious reference points out on the water. Nor alternative sites on the bank with such a clear view of most of the water. I use Google Earth to measure distances across the lake.

I deliberately set up well back from the water's edge to minimize my intrusion. My presence is merely a hobby. Their lives and natural behaviour should not be interrupted or altered just for the sake of a few [often fuzzy] photographs Some of the lake's inhabitants are rearing young. Sometimes their second or third brood of the season. I often see grebes chasing their last offspring away with considerable ferocity! They cannot afford to continue feeding juveniles which should be independent.

I am counting down the hours before I unpick [or cut] the tape which holds the lens cover to the stay-on "body bag." The round, black, dangling lens cover doubles the frontal area of the telescope!

For a scale comparison: Maximum zoom of my 12x Lumix TZ7. Gulls at about 130 yards.

Well, I finally took a pair of sharp nail scissors to the tape and severed the hold on the cap. All it would take now is to fit an open style zip instead of a closed one. I don't have the sewing machine skills for that. I shall hold the "cloth cap" in place on the telescope with a sock stretched over the stay-on case. It works an absolute treat. My wife tells me that I'm not risking contacting a local seamstress until the pandemic is sorted.

I am now thinking of taking some green, shade netting to act as camouflage by hanging it off the tripod. Camouflage "capes" are quite affordable but too inconvenient at my present level of commitment.

~~