How good are LPL enlarger lenses?

<p>I like to know the quality of LPL lens. How good they are when they are compared to Rodenstock Rodagon

or Schneider componon-s? I am consider a LPL 150mm F4.5 for my LPL 7451 enlarge

r

.</

<p>If you are using a glass carrier and your enlarger is properly aligned then they are not even remotely close to the performance of a Rodagon or Componon S</p>

<p>I use the normal carrier without the glass (135, 6X6, 4X5). I will use three sizes of film to do enlarge. Currently I have a 80mm Rodagon and I am looking for 50mm and 150mm. So I may focus on Rodagon (may be apo) and componon (may apo) or nikkor el lens. Let me know if I am right. Currently I will focus on B&W and later may try color.</p>

<p>David,<br>

There aren't any enlarging lenses that can perform to their design parameters in a glassless carrier. All enlarging lenses, from the cheapest to the most expensive, require a glass carrier and proper alignment to perform optimally. If you are not going to do that then spending the extra money on a high quality lens will not deliver the quality boost that you may expect.</p>

<p>LPL make great enlargers, but they don't make or market good lenses. A 150mm enlarging lens with a maximum aperture of f/4.5 is likely to be a cheap 4 element design - don't touch it. Every quality 6 element LF lens, such as El-Nikkor, Rodagon and Componon-S, is limited to f/5.6.</p>

<p>Used enlarging lenses cost very little these days, so don't mess about with anything second-rate, get one of the "big three" mentioned above and expect to pay around the equivalent of US $100 - $150.</p>

<p>BTW, I've worked in quite a few professional darkrooms and NONE of them used glass carriers. The marginal improvement in film flatness is more than offset by the nuisance of dust and Newton's rings, or showing the crinkle texture of AN glass if the lens is stopped down too far or a point-source is used. Think about it, there's no glass sandwich or pressure plate to flatten sheet film in the camera, so why should a glassless carrier present that much of a problem in an enlarger? And yes, I can easily see the difference in print quality between a good lens and a mediocre one when using a glassless carrier. If the grain is sharp into the corners, where's the problem? I suspect that most advocates of glass carriers have never tried a properly designed glassless one, or they just love the smell of spotting ink.</p>

<p>Joe,</p>

<p>First dust settles on negatives, slides, paper as well as glass. If you have a glass carrier in a clean darkroom you simply blow any dust off with a good air blower. Just like you will do anyway. Second, the Newton Rings may form when a hard smooth surface, like glass, comes in contact with another smooth surface like the base side of the film. To prevent this from happening the AN glass should always be on the base side of the film. Not on the emulsion side. Next when you focus the enlarger you are focusing on the emulsion side of the film not on the base side. That means that the AN glass is not in the plane of focus. Lastly the reason you need a glass carrier is because film naturally sags and the heat of the lamp in an enlarger will make the film pop in and out of focus. The reason for glass in the first place is to ensure that the negative or slide is as flat at the end of the exposure as it was at the beginning of the exposure, and to ensure that it was flat to begin with.</p>

<p>A glassless carrier simply cannot hold the film flat or keep film from popping. Therefore you cannot get the optimal performance of any enlarging lens.</p>

<p>I've fabricated a glass carrier for my D-2 which only uses one piece of glass on the top of the negative - but this only works for roll films. I use a two sided glass carrier for 4X5. Having said this, I also know it is possible to get excellent (as in sharp) results without glass - by "pre-heating" the negative prior to focussing - then again just prior to exposure... and by making sure the lens is stopped down to 5.6 or 8 (for a 50/2.8 lens) - to add a bit of depth to help compensate for any negative curvature. Also - don't focus dead-center in the neg - but more like between the center and long edge - to get a good average. My sense is that if all of these steps are adhered to, its actually possible to get a sharper, cleaner result without glass than with glass - due to the lack of extra optical surfaces. Just my two cents...and I still mostly use glass. And aside from this...the lens quality does make quite a bit of difference - and there are some bargains out there for first rate lenses - no need to go APO (which can still be pretty expensive) - but at least try for a straight up Rodagon, Companon-S, or EL Nikkor. </p>

<p>John,</p>

<p>Depth of field runs in front of the lens. Depth of focus is behind the lens and is where the film is. Depth of focus is a very small amount compared to depth of field. That is another reason to use glass. And glass above the negative has no effect on sharpness as it is not in the focus plane. You may as well say that the heat absorbing glass in many enlargers or the diffusion plate in the light path reduces sharpness. Lastly enlarging lenses are designed to be used with glass so they expect glass to be at the negative stage.</p>

<p>thanks all for your input. I almost buy a new LPL 150mm F4.5, but before I make the final payment, i posted this thread. Likely I got all information from here. Thanks again, I decide to go Big three.</p>

<p>Bob, depth-of-field and depth-of-focus become similarly sized at close focusing distances (small magnifications) and are exactly the same at a 1:1 reproduction ratio. Also the field curvature of any lens changes subtley with its focused distance, so exact film flatness may not result in any practical improvement in overall sharpness at some enlarging ratios. Film "popping" is an overrated problem that's largely a thing of the past with modern enlarger designs and polyester-based films, since both cold light source and diffusion box designs keep the negative stage relatively cool. I've only experienced the problem rarely when using a condenser light source, and not at all with diffuser enlargers.</p>

<p>The problem of dust is not trivial, and IMHO is the main thing that sets digital capture apart from film when it comes to clarity of tone and colour. Microscopic examination of any film that hasn't been produced and processed in true clean-room conditions reveals innumerable particles of surface contamination that detract from the smoothness of tone of the image. This is obviously less of a problem with large format film, but why invite dirt by providing 4 more surfaces for it to settle on? Glass has a much lower electrical conductivity than film emulsion, and so attracts and holds dust by static attraction much more readily and tenaciously than the film itself.</p>

<p>Joe,<br>

Whatever suits you is fine. But as the Rodenstock lens distributor for the past couple of decades we have factory information that enlarging lenses require glass. Period. For their optimal performance. And we used to take to consumer trade shows examples of a print from a Leica M printed at various scales at various apertures with each 50mm in the line on a Durst L1200 properly aligned, with and without glass. Their is no question that prints from a glass carrier will be superior when compared head to head with the same image. Center, edge and corner.</p>

 

<p>Has anyone ever tried multicoated AR glass in an enlarger? It should theoretically reduce the likelihood of newton's rings without the necessity for the crude mottling of AN glass, since the refractive index gradient will act like a small air gap. It also ought to be possible to have a conductive transparent (tin) coating to discourage dust accumulation.</p>

<p>Now if such a glass was available I might be persuaded to give it a try. Otherwise life's too short to mess about with endless dusting protocols.</p>

<p>Joe,<br>

There are two ways AN glass is usually made for photo purposes. Some companies save money and simply spray a substance onto the glass to break up the hard shiny surfaces. Others use a more expensive acid etched process on one side of the glass. Both work, acid etched is the least obtrusive.</p>

<p>Yep, I've tried standard AN glasses - whichever way they're made they're a mottley bunch, and all of them attract dust. I was talking about whether anti-reflection coated glass would avoid Newton's rings, and about giving the glass permanent anti-static properties. Is that too much to ask from modern technology?</p>

<p>In today's photographic market in may be too much. My company has been the world's largest supplier of glass slide mounts, plain and AN, and this is not a growth area. Also not growing is the market for new enlargers.<br>

If someone wanted to invest in the R&D to develop (no pun intended) a new type of AN glass treatment it will not come from what had been the traditional users of AN glass for photo.<br>

It would also probably end up being outrageously expensive whatever small benefit (if any) it would give over traditional AN glass types.<br>

By the way. Have you seen AN glass lenses and filter repel dust? Yes our Heliopan MC filters and our Giottos Aegis LCD protectors repel both dust and moisture but it is not the MC that does that. It is the top coat on each side that does it. The MC itself does it. As for anti-reflective glass, I have used it for decades for picture frames. You have to dust those just like you do regular glass. </p>