The negative is a 3¼ x 4¼ sheet, so she was using one of her Speed Graphics; shooting with a normal or slightly-longer focal length lens and a high enough shutter speed (Speed Graphics went up to 1/1000th sec., hence the "Speed") to permit exposure with the lens wide open would probably achieve this shallow depth of field.

Undoubtedly others noticed this photo, and that there is something slightly different about it. At first I noticed the striking use of depth of field to separate the boys from the background in this double portrait by Ms Wolcott.

I'm not familiar enough with film stocks from the 1940s to know the likely speed of the emulsion she would have used to achieve this look. When I first noticed film boxes (the ones that held the mysterious rolls of film that my dad would load into his 120 format Brownie) a lot of them were rated ASA 25. I'm pretty sure at least some faster film emulsions were available, even in 1940.

The sun is near the horizon either just after dawn or just before dusk (in my estimation). With lower light and a resulting wide-open iris, I doubt a neutral density filter would have been necessary with the film speeds of the day. It is likely a masterful use of film stock and lighting to achieve the effect. Perhaps a lot of Shorpy.com photos display similar depth of field and I just haven't noticed.

The International Center of Photography website has a page about Wolcott and her work, and of all the exterior examples shown on that site, none has this kind of artistic use of depth of field. Even though the background is never quite as sharp as the main subject, it is never this soft compared to the foreground in those examples. Her exteriors usually boast much greater depth of field, often approaching "deep focus."

But, then there seems to be something else different about the shot.

It finally struck me that these two farm lads have been caught when they were washed up and wearing fresh, clean duds. Even though that probably wasn't so unusual in real life for 1940's rural American children, it seems to be unusual for the selection of photos offered on Shorpy. So it caught my attention.

There are always layers of interest in the Shorpy offerings.

That old guy, oh, I mean youngster, on the right, is the spitting image of a 15-year-old I know. Sent the link to his grandparents. Grandma says it's him!