Is this example due to receprocity effect or something else?

Hi Everyone,

 

The image below was taken last summer but printed last night. It was Delta

3200 rated at 3200 taken with my RZ67 Pro II. I cannot recall the shutter

speed but I'll guess anywhere from a 1/2 second to 1 second. I was going for a

blur effect as people walked past this closed resturant. My question is how

did the person in the right 1/3 of the image disappear except for the foot.

There appears to be another foot more in the center although it appears it may

belong to another person. I'm amused how this came out but just out of

curiosity is it common for moving objects to disappear like this during slow

shutter speeds? There should be a person blured out in front of the glass and

metal door but there's no trace except for the foot. The door is tack sharp.

I've taken slow shutter speed photos of moving people a few times before but

usually it's the hands and feet that seem to vanish.

 

Is this an receprocity effect, or a differrent exposure error of mine or a

camera malfunction or just a normal occurance?

 

I suppose it might have to do with the distance of the moving object to the

film plane as well as the speed of the object.

 

Thanks for replies,

 

Marc<div></div>

There are a couple classic photos that show the same thing. The foot was on the ground in the same position throughout most of the exposure therefore it is clearer. The effect is often enhanced with a FP shutter, depending on the timing.

 

Reciprocity failure refers to exposure and does not account for what you were refering to above.

Marc,

 

What you see is perfectly normal for long exposures. If a moving object (person) doesn't stay still enough long enough, it doesn't comprise a large enough part of the exposure to register on the film visibly. The foot was bright enough and stayed still enough (through an entire stride during which the rest of the body was still in motion) to register visibly on the film.

 

Making moving things disappear is a useful tool sometimes. If you want to clear a crowded cathedral, just make a 20 minute exposure. Voilá, empty church.

 

Have fun,

 

www.DoremusScudder.com

Doremus has it. Reciprocity is a slowing of the emulsion's reaction to light during long exposures and is evidenced by underexposure of the negative unless added exposure is given after a certain point. Different films have different reciprocity characteristics, so check your film before expsoure to be sure you make the correct adjustments.

 

- Randy

Ah-ah! Now I'm getting a clearer picture (pun intended) Thanks guys.

You've had good analysis. Furthermore, it's only relatively dark things that disappear in long exposures, and they disappear especially well against light backgrounds. White things can leave streaks, particularly against dark backgrounds. The brighter they are, the more pronounced the effect, so it's especially true of light sources. Take a long exposure of traffic at night and you'll just see the trails of headlights and taillights.

The first live-action Daguerrotypes ever taken (by Daguerre, naturally) showed headless bodies and feet without bodies. Three to five minute exposures. Most amusing.

There is a well-known photograph by Otto Steinert which shows only the single foot of a pedestrian.

You can see the above Steinert photo at:

 

http://www.2021art.com/index.htm?/E/archiv/kuenstler/steinert.htm

Or:

 

http://www.artnet.com/Artists/LotDetailPage.aspx?lot_id=9BD6C9E65B7BBE2F

 

Easier to find. Amazing shot!

There's an example of one of my pinhole cam photos at http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00KBZc

 

Approximately 75 people went through the scene without registering on the image. If someone wearing bright reflective clothing came through, I covered the pinhole until they had passed. And if anyone stood still, I did the same.

 

In your image, the foot registered because 1. it was more stationary that the rest of the body. and 2. the light coloured bare skin has recorded on the film, whereas the clothing, most likely less reflective, as well as being mobile, has not.

 

In the pinhole image at the above link, one can just make out a ghost-like image of a man in a white shirt standing in the arch way.

 

Images such as yours, record more than just a moment in time, but rather a passage in time. I think you should experiment more with this.

 

Cheers, Kevin, Oslo.