The 7artisans 25mm Lens: Resolution And Distortion

For a compilation of the morning walk images, click here.

Bee Photographed On Corbett Avenue, San Francisco. Inset shows full frame. April 18, 2020

I added some photos to my morning walk oeuvre, and in doing so, I have found the lens to be worthy of the praise it has received.

7artisans 25mm F 1.8

Ready For Your Close Ups! The lens is capable of making reasonable closeups. Not at the true macro level, but certainly good enough to capture almost anything you might care to digitally immortalize. I found this bee on the street, and wanted to see what the lens was capable of doing. I photographed it by setting the lens at its closest focusing distance, moving the camera fore and aft until the bee was at its sharpest, and then gently pressing the shutter release. I'd repeat the process until I got an image that was sharp, or sharp enough.

If you look in the lower right hand corner of the lead image, you can see the relationship of the bee to the limits of the frame. The "big bee" is a cropping of the original image. I was impressed by the overall sharpness of the lens. The enlarged image is good enough for a normal computer display, and might even pass muster if printed as an 11x14 print. But for my purposes, this lens is totally adequate. Again, this isn't true macro performance, but if your subject is about the size of the palm of your hand, it can fill the frame. 

Barrel Distortion, 7artisans 25mm F 1.8 lens. 

Barrel Distortion: Barrel distortion is almost always present in wide angle lenses, and the less you pay, the more you get. You will notice how the ruler appears straight on its upper edge, but "curves" out noticeably the farther you get from the center of the frame. For the record, the optical center (red dot) is very close to the ruler's edge. Lines passing through the exact center will be straight, and those perpendicular to this line will exhibit mild to severe distortion based on the distance from the center. This can be a problem for architectural photographers, but is correctable in post production.

Garden, Corbett Avenue in San Francisco. April 18, 2020

Returning To The Scene Of The Crime: This is my second attempt for this crime scene photo from the Middle Earth. For this attempt, I overrode the auto-exposure setting by -2 stops so that the cyan LED eyes would appear brighter. The upside was the improved color saturation of the flamingo, which was too pale in my last effort. The overall darkness of the image added to its mystery, so this experiment was definitely to the good. See the original in this earlier posting.

San Francisco has a lot of creatives. I have no idea that plastic flamingos were targets for such wanton acts of violence.

Gratitude Bush, Corbett Avenue, San Francisco.  April 18, 2020

Since the Shelter In Place order, more and more children are left to find their own amusements, with parental supervision of course. Here, a tree was selected to carry messages of love and gratitude to the universe at large. Dozens of these laminated notes could be found hanging from the bush. Shot with the lens nearly wide open, the soft background has that smooth "bokeh" that everybody seems to want. 

Planter Box, Corbett Avenue, San Francisco. April 18, 2020

I think this image is a little hypnotic. All lines lead to the center, while the smaller plants stick to the viewer's eyes. Kidding aside, I've been looking for an image that would lend itself to a black and white rendering. 

Somehow, this image doesn't have that certain quality found in wet-processed black and white prints. It suspect it's due to the inability of a computer monitor to render a "true" black. But as a geometric study, it has its merits.

Flower Box, Corbett Avenue San Francisco. April 18, 2020.

Closeup Revelation: I just figured it out: When photographing a "bouquet", something must be in sharp focus. I chose the pistils of the center flower as my point of sharpness. Sadly, there are two factors working at cross purposes. First, you need to shoot at a relatively large aperture to minimize the depth of field. Unfortunately, lenses are seldom their sharpest when used wide open. I got the shallow depth, but not the super-sharpness that would have helped the photo work. 

Oh well. There's always tomorrow!