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Low Light Photography

30th March 2019

It’s Dark Down There


Mammoth Cave National Park, located in central Kentucky is the world’s largest system of caves extending more than 400 miles. On a recent trip with a few of our grandkids, we stopped there for a few hours to explore some of the caves.


here are the grandkids adorning the park sign

at this entrance way we had to descend about 30 steps

We arrived at the park too late to reserve a spot on one of the various guided tours. Instead we opted to take the self-guided tour.


The beginning of the cave entrance is lighted by daylight with handrails and a cement walkway. Continue walking and the outdoor light slowly disappears.

Electrical lights provide the only illumination inside, but they are relatively dim. We were surprised by the width of the cave at this point – about 30 feet side to side.


As you can see, we’re walking alongside the cave walls. The pathway is mostly hard dirt but there are cement pavers in some parts of this cave.

At this point, the cave widens considerably and the ceiling varies between 30 and 50 feet high. You’ll also notice that this area is well lighted.


One of the park rangers points out this small bat hanging from one of the cave walls. He tells us that there were hundreds of the bats at one time but they are no longer found in large numbers.

This part of Mammoth ends after about one-quarter of a mile. As we turn around and walk back towards the entrance way you can visualize the darkness of these caves.


This short clip shows the large size of the so-called “ampitheater” within the self-guided tour cave.



The steps from the cave. The self-guided tour is an easy way to explore Mammoth when you’re time limited.

Here is the wife and grandkids relaxing after their cave diving experience.



For those interested, these photos were taken with a Sony A7 III camera using a 24-240mm lens. In most cases, the ISO setting was 16000 or 32000 and taken handheld with a shutter speed of 1/15 or 1/30 and aperture as wide as f/3.5. I think the photos are of pretty decent quality considering the cave environment.

 

 



 

 

 

 

Unique Features of the Sony Alpha A55

The Sony Alpha A55 has a long list of features – some of which you may find in a few other cameras and others that are unique only to the A55. But taken together they they make the A55 a very compelling piece of equipment.

In Part 1, I talked about the “standard” features of the A55.

In this part of the review, I’ll key in on several of these features that are both unique and innovative.

The first three features are possible because of the A55’s translucent mirror.


Electronic Viewfinder

The first time I used the A55, I was surprised when I put my eye up to the viewfinder. In place of a conventional reflex viewfinder used in DSLRs, the A55 has an electronic viewfinder (EVF). The resulting image is somewhat similar to what I might see on a miniature television.

A big advantage is that the image in the EVF can be overlaid with a variety of information as you can see below.


viewfinder displaying the level gauge in the center

viewfinder displaying histogram at bottom right

viewfinder showing changeable settings
Having used a dozen or more DLSRs extensively, it took me about a week to get used to the EVF. As a wearer of eyeglasses I was able to set the built-in diopter adjustment correctly for my vision. The image is bright and clear owing to the 1.1 megapixel viewfinder screen, a high refresh rate (60fps). The EVF also has 100% field coverage. I especially like the level gauge that helps to align the horizon.

(more…)