bill_taylor2

<p>Since it acts as a hood over the viewfinder, it should block out glare. That in turn helps with focusing and composition.</p>

<p>Bill C, you may be right about the graphs. But since all I have are what the manufacturers publish, I can't just assume too much else. Ideally the density curves should follow an elongated S curve, and the measurements for useful range come from the upper and lower knees. But if the charts don't show the knee, how can I assume where I think it ought to be?</p>

<p>Short and sweet, I spent a few hours looking at log exposure and density charts. Did some estimations and came up with this. Obviously it is all my opinion, you are free to reinterpret as you please. In particular, how I derive the exposure offset, and using 1.5 stops of "toe" is purely arbitrary. I just like the idea of having a little bit of (theoretically) usable detail in slide highlights and negative shadows.</p>

 

<p>http://www.largeformatphotography.info/fstop.html</p>

<p>It is a great article, read it. But to answer your question, read the Summary at the top, then skip down to "Finding the optimal f-stop to balance defocus and diffraction" near the end. Essentially, Depth of Field gets better with stopping down, but Diffraction gets worse when you stop down too much. There is a sharpness sweet spot of optimization, and once you know what to do, you know what f-stop to pick. I have a copy of the table in my field notebook.</p>

<p>Ken Rockwell, who is a very knowledgeable and no-nonsense guy, has a much longer winded (one might even say blowhard) description of the same phenomena, if you really want every aspect spelled out for you. http://www.kenrockwell.com/tech/focus.htm</p>

 

<h2>For some reason it won't let me link that. so here it is in plain</h2>

<h2><a title="Permanent Link: Resolving the iPhone resolution" rel="bookmark" href="http://blogs.discovermagazine.com/badastronomy/2010/06/10/resolving-the-iphone-resolution/">http://blogs.discovermagazine.com/badastronomy/2010/06/10/resolving-the-iphone-resolution/</a></h2>

 

<p>Eyeball resolution: all / most / some is revealed here:<br>

<a href="http://blogs.discovermagazine.com/badastronomy/2010/06/10/resolving-the-iphone-resolution"></a> Discover Magazine, Resolving the iPhone resolution</p>

 

<p>Nikolai,<br>

All I can think of at this point is to check the basics. Film flatness, swings and tilts and shifts.<br>

Look at the front and rear elements in the mount to be sure they are not cross threaded. And thn examine the lens elements to see if somthing has become uncemented.<br>

I have one of these lenses and it has been quite good for me. No noticable curvature.<br>

Bill</p>

<p>Just to double check, I reread my entry. Sure enough, it does say you can change the viewing distance number. And you can in fact enter a different number in that cell. And the math is correct. So, if you desire to view your prints from 200 feet off, feel free to adjust accordingly. 200x12 = 2400 inches. <br>

Scott, it is more of a line pairs thing. If there were 3 black bars AND two white ones (to provide contrast) in a height of 5 arc minutes, that is 1 arc minute per line, but 2 arc minutes per line pair. Without the pairs, you would have five black lines, which you could see (as a block), but not distinguish.</p>

 

<p>It is a minimum, not a maximum. If the scan doesn't look right, you can go with more.</p>

<p>I know this have been done to death, but I just went through the exercise myself. What scan should I use for a given negative and print combination. So I went back through first principles to work out the (semi) optimum scan pitch for a given final print. <br>

The question is this: for a given assumed viewing distance, a given assumed visual acuity (the smallest thing you can see), and various negative/transparency sizes and final print sizes, what scan pitch (dpi) should I use?<br>

The assumption for the spreadsheet is viewing from 10 inches out. This is basically critical viewing right on top of the print. Kodak uses a 14 inch viewing distance, I've soon others use 8 inches. The spreadsheet number can be changed easily enough. If you are making a billboard, you might use 20 feet (240 inches). It is your application. <br>

Visual acuity is just how good your eyes are. I used 2 minutes (2/60 degrees) as a pretty strict limit. That really is eagle eyes for humans. You might want to relax it to 3 - 5 minutes.<br>

From there you work out the dot pitch on the print, then back through the magnification to find the dot pitch on the negative. From 10 inches, 2 minutes works out to about 172dpi on the print. A lower pitch (e.g. 160dpi) would be coarse enough to see individual dots. A higher pitch (e.g. 200 dpi) would be fine enough to visually blend. The magnification is just how big you are blowing up the negative. I assumed the whole negative is being printed, which is often not the case, but you have to start somewhere. Digital sampling theory suggests that, for accurate reproduction, you need to sample at twice the frequency of the highest frequency of interest. That just means there is an extra factor of 2 involved in the sampling. Do the math, and you come up with the pitch the scanner should run at in order to get a good printable scan file.<br>

Keep in mind that film has an ultimate resolution, usually in the 50 - 64 lp/mm range. That works out to 5000 - 6500 dpi, way higher than most people ever get to. So generally speaking, the film has more information than the scanner can capture. But on the other hand, you probably will never print anything that will show that detail, unless you are just making extreme enlargements.<br>

I also estimated the file size, based on a 24 bit scan. Your mileage will vary.</p>

<p> </p>

<p>Good news! I heard from the Kodak Pro Products division, and they recommended the "Kodak Color Separation Guide and Gray Scale" there are two sizes, the 8" Q-13 and the 14" Q-14. It is a paper sheet with 20 graduated steps from white to black, plus several standard colors for print calibration RGBCYMK. Samys didn't have any in stock online, but B&H did, so I just ordered one.</p>

<p>I may still follow up on that Kodak color book though. I know I have the B/W one from the 90s around here somewhere.<br>

Thanks all!<br /> </p>

<p>Joe,</p>

<p>Thanks, I'll look. I'm fully expecting the color shift with long exposures. Typically I've seen it go blue, but every film is different. What I really want is to get numbers for decent density and shadow detail. Digital correction will be the order of the day after that. Just one click in Photoshop, right? Well, maybe four or five clicks.</p>

<p>Les,<br>

Thanks for the shots. Where did you get a shutter with 1/6 and 1/3 second? I'm not after the latitude per say. I'm really just wondering what the recip failure is at low light, long exposure. Although, establishing latitude is a byproduct of the test.</p>

 

<p> With spring coming and the new Ektar 100 sheet film coming out, I want to know what it can do in long exposure. The tech sheet for the film just says no corrections needed up to 1 second. But we all know recip failure kicks in somewhere. I'd like to know where. My first thought was to get a black target, a white one, a gray card, and some text and make some exposures. Find the one that looks like the text is readable and the three cards are evenly spaced.<br>

But then I seemed to remember a Kodak publication. They had a calibrated gray scale target of some kind. 8 or 10 or 12 steps from black to white. If I could get that, I could just shoot it and get a much better idea of when the film is recording a relatively wide range. Does anyone remember the name of this thing, and especially where I can get one?</p>

 

<p>Simple question for the group: Does anyone know of a good low light, or very low light meter? I've seen plenty that go down to EV 0, but none below that. -4 or even -8 would be nice. But I'm not holding my breath.</p>

<p> </p>

<p>I have stored D-76 long term for years. My tips are<br>

1. Use real glass bottles. I mix 1 gal at a time and store it on gallon jugs with good screw caps. Plastic breathes and oxygen will get in eventually. Some plastic is better than others, but glass is literally 100 times better.<br>

2. For partially filled bottles, flush the headspace with "canned air". That could be Dust-Off (or equivalent), or dry nitrogen gas if you have it. You want to displace any oxygen/air that has got into the bottle. Do this as soon as absolutely possible after you pour some developer out, then tightly cap the bottle again. I will sometimes invert the canned air a bit so some of the propellant liquid expands into the headspace. This assures any air/oxygen will be pushed out.<br>

3. When you mix the developer, use boiled and cooled de-ionized water, and do your best not to splash. Boiling drives the oxygen out of the water. De-ionized is purer for longer shelf life. Minimal splashing keeps air out of the developer when mixing and stirring. If you can, flush the bottle with canned air before you mix, so the fresh developer never really touches real air.<br>

4. Don't expect used developer to last any length of time. Or to put it another way, don't reuse developer. I use dilute developement, so that each batch is fresh developer. The dilution water should be boiled and cooled de-ionized water too, but it doesn't really matter that much. Tap is OK (since you'll be throwing it out in a few minutes anyway).<br>

5. Check the color as it comes out of the bottle. Fresh D-76 should be clear with no tint. If it is cloudy or tinted (yellow), you've got problems. If it is like apple juice, it is long gone.<br>

Using this method I've used developer over a year old with great results. Once a partially filled bottle was over 18 months and was only just showing a hint of color.</p>

 

<p>I suspect they mean something a bit more obvious, in the Hollywood mode. If your wife shows up in bikini and heels, it could become an issue. Same goes for you, I suppose :)</p>

 

<p>The latest forecast says moderate warm and partly cloudy through most of the day, with a chance of rain in the afternoon. </p>

<p><a href="http://www.wunderground.com/cgi-bin/findweather/getForecast?query=91011&hourly=1&yday=79&weekday=Saturday">La Canada, CA</a></p>

<p>A little spring shower won't be too bad people! Get out and make some images with your compadres!</p>

 

<p>The latest forecast says moderate warm and partly cloudy through most of the day, with a chance of rain in the afternoon. </p>

<p><a href="http://www.wunderground.com/cgi-bin/findweather/getForecast?query=91011&hourly=1&yday=79&weekday=Saturday">La Canada, CA</a></p>

<p>A little spring shower won't be too bad people! Get out and make some images with your compadres!</p>

 

<p>The latest forecast says moderate warm and partly cloudy through most of the day, with a chance of rain in the afternoon. </p>

<p><a href="http://www.wunderground.com/cgi-bin/findweather/getForecast?query=91011&hourly=1&yday=79&weekday=Saturday">La Canada, CA</a></p>

<p>A little spring shower won't be too bad people! Get out and make some images with your compadres!</p>

 

 

<p>My goal was to set something up for all Photo.net photographers with any interest to all show up on the same day in the same place. We all shoot, ask questions, get answers, chat, and generally get the photo geek on in a nice place.<br>

I spoke with a manager at Descanso Gardens about a group of photographers showing up. He was OK with it, but they have concerns.<br /> <br /> A. No models! The garden is there for the nature of it. Getting the flowers, shrubbery, trees etc is all fine. NO model shooting.<br>

B. No reflectors or extraneous lighting. They don't want to see big reflector panels being manhandled around. Tiny handhelds might be OK. The big thing is No Blocking the Paths.<br>

C. Tripods and Bags OK, but again Don't Block the Paths. We do not get exclusive access to the park, so other people will want to come and go around us.<br /> =-=-=-=-=-=-=-=-=<br /> There are other Official Rules too.<br /> 1. Professional Photographers will be charged a fee. Please check in at the Rentals Office to obtain Photography Guidelines for professional photographers.<br /> 2. Some areas of the Gardens are not available for non-professional tripod photography, painting and drawing, or group activities<br /> 3. Benches may not be used as easels or to hold equipment.<br /> 4. All Gardens-sponsored activities, such as classes, filming, docent tours, landscape and maintenance projects, will have priority. You may be asked to relocate your activities.<br /> 5. No activities are permitted that may disturb or limit the experience of other Gardens visitors.<br /> 6. Please keep the grounds clean. Remember to pick up all trash ans do not dump any material, including paint water, on the ground or in water features.<br /> 7. No food is permitted inside the Gardens. A picnic area is available out side the Gardens and you may eat food purchased at our Cafe in the Cafe Coiurtyard.<br /> =-=-=-=-=-=-==-=<br /> As you can see, they are sensitive to Professional Photographers and Painters, and to clutter and blocking the park to all users. We are not classed as pros, but the tripods and lighting was the concern. They charge the pros extra, and they need permits on days and times of usage. Assuming we don't all show up with a van full of equipment, they won't freak out.<br>

So with all of that in mind, I propose 10am at the front gate of Descanso Gardens in LaCanada (Highway 2 (Angeles Crest Hwy) at I-210). Pretty much just walk up to the gate, pay the fee, and walk in. Parking is free. If they ask, tell them you are there with the Photo.net group. Hopefully they won't care or look at you funny.<br>

If you think you might want to go, Please say so here by Friday. I need to warn them about numbers on Friday afternoon.<br>

Thanks!</p>

 

 

<p>My goal was to set something up for all Photo.net photographers with any interest to all show up on the same day in the same place. We all shoot, ask questions, get answers, chat, and generally get the photo geek on in a nice place.<br>

I spoke with a manager at Descanso Gardens about a group of photographers showing up. He was OK with it, but they have concerns.<br /> <br /> A. No models! The garden is there for the nature of it. Getting the flowers, shrubbery, trees etc is all fine. NO model shooting.<br>

B. No reflectors or extraneous lighting. They don't want to see big reflector panels being manhandled around. Tiny handhelds might be OK. The big thing is No Blocking the Paths.<br>

C. Tripods and Bags OK, but again Don't Block the Paths. We do not get exclusive access to the park, so other people will want to come and go around us.<br /> =-=-=-=-=-=-=-=-=<br /> There are other Official Rules too.<br /> 1. Professional Photographers will be charged a fee. Please check in at the Rentals Office to obtain Photography Guidelines for professional photographers.<br /> 2. Some areas of the Gardens are not available for non-professional tripod photography, painting and drawing, or group activities<br /> 3. Benches may not be used as easels or to hold equipment.<br /> 4. All Gardens-sponsored activities, such as classes, filming, docent tours, landscape and maintenance projects, will have priority. You may be asked to relocate your activities.<br /> 5. No activities are permitted that may disturb or limit the experience of other Gardens visitors.<br /> 6. Please keep the grounds clean. Remember to pick up all trash ans do not dump any material, including paint water, on the ground or in water features.<br /> 7. No food is permitted inside the Gardens. A picnic area is available out side the Gardens and you may eat food purchased at our Cafe in the Cafe Coiurtyard.<br /> =-=-=-=-=-=-==-=<br /> As you can see, they are sensitive to Professional Photographers and Painters, and to clutter and blocking the park to all users. We are not classed as pros, but the tripods and lighting was the concern. They charge the pros extra, and they need permits on days and times of usage. Assuming we don't all show up with a van full of equipment, they won't freak out.<br>

So with all of that in mind, I propose 10am at the front gate of Descanso Gardens in LaCanada (Highway 2 (Angeles Crest Hwy) at I-210). Pretty much just walk up to the gate, pay the fee, and walk in. Parking is free. If they ask, tell them you are there with the Photo.net group. Hopefully they won't care or look at you funny.<br>

If you think you might want to go, Please say so here by Friday. I need to warn them about numbers on Friday afternoon.<br>

Thanks!</p>

 

<p>My goal was to set something up for all Photo.net photographers with any interest to all show up on the same day in the same place. We all shoot, ask questions, get answers, chat, and generally get the photo geek on in a nice place.</p>

<p>I spoke with a manager at Descanso Gardens about a group of photographers showing up. He was OK with it, but they have concerns.<br>

<br /> A. No models! The garden is there for the nature of it. Getting the flowers, shrubbery, trees etc is all fine. NO model shooting.</p>

<p>B. No reflectors or extraneous lighting. They don't want to see big reflector panels being manhandled around. Tiny handhelds might be OK. The big thing is No Blocking the Paths.</p>

<p>C. Tripods and Bags OK, but again Don't Block the Paths. We do not get exclusive access to the park, so other people will want to come and go around us.<br>

=-=-=-=-=-=-=-=-=<br>

There are other Official Rules too.<br>

1. Professional Photographers will be charged a fee. Please check in at the Rentals Office to obtain Photography Guidelines for professional photographers.<br>

2. Some areas of the Gardens are not available for non-professional tripod photography, painting and drawing, or group activities<br>

3. Benches may not be used as easels or to hold equipment.<br>

4. All Gardens-sponsored activities, such as classes, filming, docent tours, landscape and maintenance projects, will have priority. You may be asked to relocate your activities.<br>

5. No activities are permitted that may disturb or limit the experience of other Gardens visitors.<br>

6. Please keep the grounds clean. Remember to pick up all trash ans do not dump any material, including paint water, on the ground or in water features.<br>

7. No food is permitted inside the Gardens. A picnic area is available out side the Gardens and you may eat food purchased at our Cafe in the Cafe Coiurtyard.<br>

=-=-=-=-=-=-==-=<br>

As you can see, they are sensitive to Professional Photographers and Painters, and to clutter and blocking the park to all users. We are not classed as pros, but the tripods and lighting was the concern. They charge the pros extra, and they need permits on days and times of usage. Assuming we don't all show up with a van full of equipment, they won't freak out.</p>

<p>So with all of that in mind, I propose 10am at the front gate of Descanso Gardens in LaCanada (Highway 2 (Angeles Crest Hwy) at I-210). Pretty much just walk up to the gate, pay the fee, and walk in. Parking is free. If they ask, tell them you are there with the Photo.net group. Hopefully they won't care or look at you funny.</p>

<p>If you think you might want to go, Please say so here by Friday. I need to warn them about numbers on Friday afternoon.</p>

<p>Thanks!</p>

 

<p>My usual lens hood is the dark slide for the film I'm exposing. Usually works great. But I got caught recently while using a 65mm and pointing a little too close the sun. The exposure looks great, the framing of the subject is near perfect. But in the upper left corner is a lovely image of my shirt cuff, wristwatch, hand, and dark slide.<br>

No flare though. :-)</p>

 

<p>j falth beat me to it. I have the Photobackpacker setup for a large format camera. I love it. Plenty of secure storage, and room around the edges to stuff a few extras. All based on a backpack made by a no-kidding backpack company! However, it is a full sized pack, larger than a day pack. Be sure to look over that option carefully.</p>

 

<p>Vinny, my mentioning "Point and Shoot" was more ironic than serious in our case. I have nothing against pocket digitals exactly, but they aren't really comparable to field cameras.</p>

<p>If they have a prejudice against LF, maybe something can be done to dispel it. I might be able to get by there next week. If I bring my typical traveling rig, (large backpack, small film bag, tripod) maybe they'll back down a bit.</p>

<p>By the way, I got one hit from someone in Nature. He suggested Mar 14, since he's off to Indonesia by Mar 21. </p>

<p>And again By The Way, is there a better way to promote an event on Photo.net? This is one of the few forums that allows it. The 35mm and MF seem quite militant against non-equipment questions.</p>