Transfer of image through lens onto film - HOLGA

[mtorti]

My question isn't obscure in nature, but in practice I'm not so sure.

I am interested in knowing the process the image goes through when entering the lens of a HOLGA camera and onto the film. Does the image get flipped, like in conventional cameras, or is it simply transferred as is.

I did a test last night by opening the back of the camera and setting the shutter to bulb. With the shutter open I moved my finger in front of the lens. The image appeared as it is in reality, not flipped and not backwards. The leads me to believe that the negative receives the image with no transformation. Is this correct?

I have researched this question, and every site provides the flipping of the image within the camera. I remember from basic photo way back in the day, this process being taught as well. So is this because the lens of a HOLGA camera (cheaper and non-professional) treats the image differently?

I do experimental photography and this information is vital to my next project. I have a shoot this weekend and no time to do a test run. This will be the beginning of a shooting style I am about to focus on, but I'd like the first run to come out with the intended results. All I can say is how the image reacts within my HOLGA is vital to my work. I'll have an answer after this first roll, but I wanted to see if any photo geniuses have insight beforehand.

So will the image be flipped; flipped upside-down and backwards; transfer backwards; or simply transfer straight onto the negative? Remember this is for HOLGA only.

For imagery-friendly responses: If the subject wears the shirt TOAT, am I right to assume that by entering the camera and transferring onto the negative, the light-sensitive side of the negative will be burned with TAOT? Or does the entire image become flipped upside-down?

 

[Moglex]

I cannot find any reference to the Holga behaving any differently to any other camera in this respect.

All cameras produce an image at the film/sensor that is inverted and swapped left to right. Unless the Holga had some extraordinary innards it will do just what any other camera does. (Although in normal terms, a lot worse!)

One normally holds the slide/negative in such a way the the image appears the 'right' way around if that is important.

 

[Steph]

I am with Moglex on that one. The lens on a Holga is a simple meniscus, so the image at the film plane should be inverted (top to bottom and left to right).

 

[mtorti]

I'd agree with you both, but why then during my test did I find the image to be transfered as if looking through a simple plane of glass? Does it have to do with the back of the camera being off, or something else?

 

[Moglex]

I'd agree with you both, but why then during my test did I find the image to be transfered as if looking through a simple plane of glass? Does it have to do with the back of the camera being off, or something else?

Take a magnifying glass.

Look through it. Everything is the right way around. (No matter how far or near you hold it to your eye/the subject).

Now find a bright source (a small window on a bright day is good). Project an image of the window onto a sheet of paper. It's the wrong way round in both dimensions.

Now work out why that is.

It's actually very obvious once you 'get' it.

 

[mtorti]

Thanks Moglex, although my question still needs answered. I "get" camera optics. I understand that the image is flipped and inverted. Why, though, with the naked eye through the lens does the imagery not appear this way?

Does it have to do with there being a medium on which it is transferred?

 

[Moglex]

Thanks Moglex, although my question still needs answered. I "get" camera optics. I understand that the image is flipped and inverted. Why, though, with the naked eye through the lens does the imagery not appear this way?

Does it have to do with there being a medium on which it is transferred?

Do a ray tracing from the object you are looking at right through to your retina. All should then become clear - if it isn't already.

(It's not that I don't want to tell you but I'm sure you'll be more satisfied when you get it for yourself.)

 

[mtorti]

I'd be most satisfied with an answer - like I said, I don't have a bunch of time.

 

[Moglex]

I'd be most satisfied with an answer - like I said, I don't have a bunch of time.

Your eye is a lens.

If you did a ray trace from the top of an object, through the Holga's lens to your retina, it would travel down towards the bottom of the Holga lens then up from the bottom of the lens to the top of your eye thence down towards the bottom of your retina and thus form part of an inverted image which is how all normal things appear at the retina.

Thus it would seem to be quite normal.

When it hits the film it has not been through the lens in your eye and is hence recorded upside down and the wrong way around.

 

[mtorti]

Great thanks, this helped out a ton and hopefully the shoot goes well. I figured it had to do with the medium, but thanks Moglex, for not dumbing it down in the slightest.

 

[Stosh]

I don't know anything about a HOLGA camera, but if you look through a lens at a distant object with a positive focal length (all "normal" camera lenses have a positive focal length), then the image appears in the correct orientation if your eye is between the object and the focal point. As you move the lens away from your eye the apparent object size increases until you hit the focal point, then the image reverses once you hold the lens far enough away to be beyond the focal point. A note about the magnifying glass reference: The image through a magnifying glass stays in the correct orientation because the object is normally inside the magnifying glass's focal length. If you move the magnifying glass far enough away from the object as to be outside the focal length, the image will indeed appear inverted and reversed if your eye is also beyond the lens' focal length. This normally doesn't apply to camera lenses unless they have specialized macro optics that will allow it to change the rules of simple lenses. Normally you cannot take a picture of something closer to your lens that its focal length.

So to answer your question you should visually see a correctly oriented image if either your eye, or the object, is inside the lens' focal length. If the object and your eye are *both* further away from the lens than its focal length, the image will be inverted and reversed.