US$ 5.00 Fresnels for tight budgets

[Foto Ludens]

Hey folks,

As some of you know I recently dove into 8x10, and having had coverage problems on my first neg (forgot to check corners after tilts) I decided to look for cheap fresnels.

I found some at http://www.anchoroptics.com/catalog/product.cfm?id=24, and bought an 11.25" square fresnel with a 6.5" focal length for 5 dollars ($11.25 or so after tax and shipping). I figured that for this price I could risk it.

I proped up the lens on the back of my focusing screen and the results were very noticeable. The whole screen lit up, with very little darkening on the corners (162mm lens). I then put some velcro on the fresnel and on the back, in such a way that I can compose with the fresnel on and take it off for fine focusing.

Sure, it's not an elegant solution, and the fresnel curves are quite noticeable, but for those of us with little money to spare it might be worth a try.

Just thought that I'd throw the idea out here...

André

 

[Dave Parker]

You can pick up book page sized fresnels at Office Depot, Office Max and Staples for about $8.00, they are very course, and there focal length varies a great bit from what is claimed, which I suspect could be the case in these as well..and the concentric lines in this size can be very disturbing..

dave

 

[Terence]

Edmund Scientific has similar ones as well. They are labelled as "surplus".

 

[Foto Ludens]

Yeah, these are surplus fresnels as well(anchor is an optical surplus store).

And I agree with dave, the lines are quite noticeable, and I don't think that this set up is an alternative to a quality screen. At the same time, it is much better than nothing. I'm sure that it will make composing much easier for me (I'll try it out this weekend).

take care,

André

 

[jl]

This place looks pretty good: www.3dlens.com relatively cheap with a variety of sizes, focal lengths and groove spacings.

 

[Dan Fromm]

Edmund Scientific has similar ones as well. They are labelled as "surplus".

Anchor is Edmund's outlet store. I live about three miles from them.

 

[Terence]

That would make sense. Learn something new every day.

 

[Capocheny]

Andre,

Why don't you just consider buying one of the Satin Snow screens? I've been using one on my 4x5 for the past couple of years. They're really bright and no concentric rings!!!!

And, I've just ordered a 5x7 and another 4x5 version for my Dorff.

Cheers

 

[j_landecker]

Andre,

Why don't you just consider buying one of the Satin Snow screens? I've been using one on my 4x5 for the past couple of years. They're really bright and no concentric rings!!!!

And, I've just ordered a 5x7 and another 4x5 version for my Dorff.

Cheers

As nice as the Satin Snow screens are, they have no magical attributes and wide angle lenses will give the usual hot-spot which only a fresnel can even out. A Bosscreen with fresnel is still my favourite combination for all-round evenness of illumination and focusability.

 

[Dave Parker]

As nice as the Satin Snow screens are, they have no magical attributes and wide angle lenses will give the usual hot-spot which only a fresnel can even out. A Bosscreen with fresnel is still my favourite combination for all-round evenness of illumination and focusability.

I don't know that there are any magic screens out there, the law of optics comes into play with all screens, the Boss screens as nice are they are, also have shortcommings as does the Maxwells and my screens as well, out of all the different combinations I have worked with, the fresnel/glass combinations are the most anoying to me, but it all comes down to personal prefrence is all it is...

Dave

 

[j_landecker]

I don't know that there are any magic screens out there, the law of optics comes into play with all screens, the Boss screens as nice are they are, also have shortcommings as does the Maxwells and my screens as well, out of all the different combinations I have worked with, the fresnel/glass combinations are the most anoying to me, but it all comes down to personal prefrence is all it is...

Dave

Hi Dave, not to single your screen out (although I do have one of yours so I can speak from my experience as to its lack of magic powers!), but there seems to be a lot of talk out there about screens where people praise whichever one they're enthusiastic about as being particularly bright and even and not needing a fresnel, as if it doesn't obey optical principles. This is what many comments I read about the Bosscreen said, and when I finally got one and put it on my camera, I immediately thought that the evenness of illumination with a wide angle lens was only marginally better than what I had replaced (a stock Linhof screen). I popped my fresnel on and, there was my evenness back again, along with the grainless sharpness of the Bosscreen, and I've been very happy since. So as you point out these systems all have trade-offs, and it certainly is personal preference as to what an individual likes...

Jim

 

[Dave Parker]

Hi Dave, not to single your screen out (although I do have one of yours so I can speak from my experience as to its lack of magic powers!), but there seems to be a lot of talk out there about screens where people praise whichever one they're enthusiastic about as being particularly bright and even and not needing a fresnel, as if it doesn't obey optical principles. This is what many comments I read about the Bosscreen said, and when I finally got one and put it on my camera, I immediately thought that the evenness of illumination with a wide angle lens was only marginally better than what I had replaced (a stock Linhof screen). I popped my fresnel on and, there was my evenness back again, along with the grainless sharpness of the Bosscreen, and I've been very happy since. So as you point out these systems all have trade-offs, and it certainly is personal preference as to what an individual likes...

Jim

Hi Jim,

I agree, the biggest factor in the screen game is personal preferance, I own at least one copy of each of the enhanced screens as well as my own and a couple of others sceens who have done them over the years and I use a true ground glass without a fresnel, I think different things can be added or subtracted to make things better or worse, again, depending on the person shooting it..

I always tell everyone, shoot what makes ya happy...I know I do.

Thanks..

Good shooting.

Dave

 

[laz]

Can someone elaborate on the advantages of a fresnel, what and how they add? With just a few months into LF I have learned the short comings of GG but none of the secrets of making things easier.
-Bob

 

[Peter De Smidt]

Fresnel lenses of the right focal length make the brightness of the ground glass more even. For example, with my 8x10 and certain lenses there is a bright spot on the ground glass, but the rest of the glass is quite dark. When I move the position of my eyes, the bright spot moves. That way I can check the different areas on the ground glass for sharpness and composition. It'd be nice, though, to be able to clearly see the whole ground glass at once, as a compositional aid. Adding a fresnel should help with this. The downsides are the cost, fragility, and grooves. If the concentric grooves on the fresnel are too large, they can obscure fine detail. That's why a number of people compose with the fresnel on the camera but remove it for fine focus. Some fresnels have extremely fine grooves, and these are what camera manufactures and specialty screen makers use.