jerry2

Mark, how do you adjust the Sekonic spots to work at 18%? The 778 and new 680 does not allow for such.... unless you change the film speed which would effect both incicent and spot readings? I am very interested in learning, as I forget this quite often!!!!

Mike, .... So I asked what if the user is generating 16 bit scans from the Imacon and working with them in Photoshop as 16 bit images. In that case, he said, no difference.

 

As noted above, PS has very few controls that work in 16 bit, so if you plan to archive scans in 16 bit they will not be corrected.

 

next, if you scan in 16 bit, its better to make as many corrections as you can before downsizing to 8 bits. This is another benefit of scanner software that works in 16 bits. In the end, you will have a much cleaner file vs. starting in 8 bits and then doing your corrections. But a lot of this depends on how anal the user is and the inteneded purpose of the final output.

 

In some ways I disagree with the Imacon rep. The scanner software can dictate how the scan is captured first...the goal would be to capture the D range close to what the image has to offer during the scan. Better software will even allow you to set the D range to match botht he high and low D range values. Also, grey balance in the scanner software is very useful to get ALL the colors correct.

 

The other issue I would concern yourself with is resolution. I have read many articles about scanners not acheiving anywhere near the resolution they claim. This can vary from machines of the same model and different model machines. Very few people ever take the time to scan a test chart to determine the scanner can reach the desired scanning resolutions. Howteks are notorious for this, just ask Phil at Aztek. (He may change his tune now that he bought out Howtek) This is definetly true also with flat beds.

 

You may also consider just how much dpi you need. I have recently learned that scanning color film greater than 2800 dpi is a waste of time and produces inferior scans...if you need larger files, its better to up-rez vs. scanning past what the films resolving capacity. Most color film maxes out at about 2500 dpi (49 lpmm), while Velvia can be pushed to about 3000 dpi (59 lpmm).

 

Also, watch out for the new breed of flat beds hitting the market. canon just introduced a flat bed that scans reflective up to 8.5 x 11.5" and film up to 4x5" at 3200 x 4800 optical DPI. It's the Canoscan 9900F. Epson has released a 3200 dpi optical scanner in Japan, USA usually gets it a month or two later. Both of these scanners will retail for $400. I know it seems hard to beleive that you can buy a scanner at this price which will perform as advertised, but we shall wait and see.... as digital keeps getting better and better every 6 months.... Remember the first calculator costs $150, now you can buy a better one for $3.

From a reputable dealer....

 

Mr.Sakai died, his widow and the accountants tried to run the show without to much success......the brother was brought back into the business (he was the true camera engineer but was overlooked by the father as he was the younger brother) he sorted the mess out and made sure the company dropped all the nonsense which no longer had commercial viability and has now set up another company to manufacture the cameras.I guess making Sakai bankrupt was a financial decision to get rid of the debt......

So, yes, we are now getting deliveries if somewhat slowly and the cameras are as good as ever.......

Drum scanning is no different than scanning on a flat bed. The only real difference is you have to learn to mount film onto a drum. Based on the type of film you are mounting on the drum and the magnfication you are trying to achive, this can be anything from simple to very cumbersome.

 

If you are scanning 35mm images on a drum they are easy to mount. If you use large image such as 8x10 on a drum, they are harder to mount, since the image takes up almost the entire drum area, unless you are using an oversized drum. At less than 4x magnfication you do not need to wet mount, but over 4x we mounting is mandatory. It requires a piece of clear acetate over the film. Scanning fluid is placed above and below the film. The acetate holds the fluid by securely taping all the sides. Its the wet mount process that quite often produces superior results, its not neccessarily the drum scanner itself. Only Scitex makes a flat bed that accepts a wet mount and it costs in the $35k range last I checked.

 

software is a different animal. Not all scanning software works with all scanners. For example, if you use a Howtek scanner and use a Mac, Trident is the only software available, at a cost of approx. $1500. Other scanners use a variety of different software. Be forwarned, drum scanning software companies are not looking to improve their products.... its sometimes even hard to get tech support as this is a diminishing market. Most of the software I have seen has very poor manuals, or no manuals. Its best if you plan to own and operate a drum scanner to find someone who can teach you all the tricks of the trade....then it seems like a breeze, but figuring out everything on your own can be quite frustrating.

 

The last thing to worry about is repairs. Some units no longer have spare parts made and other units charge exhorbitant rates for spare parts. Its not uncommon to buy a used drum scanner for $4k and a board breaks and costs $6k to replace it. Very frustrating!

 

Hope this helps..

Does anyone know how what diffraction rules the Packard shutters follow? I assume they must be different than a standard lens shutter?

> Just to clarify... I don't think that all meters are calibrated to 18% grey. Sekonic meters are calibrated to 13% grey from what I've been told. Not that it makes a huge difference.

 

Well, the difference between 13% and 18% is 1/2 stop, if your off 1/2 stop from the start on every shot, thats not a good starting point. BTW, most spot meters are calibrated to 13% grey, only a few use 18%. Sorry don't remember which ones, check user manuals.

 

Some points to try help ya Scott. Using EOS for spot meter can be dangerous with zoom lenses. I know all my spot meters are dead on, yet I can never get my spot meters to jive with my EOS when using a zoom lens. And the odd part is, my EOs always gives good exposures. I think its possible the camera is calculating some light loss in the zoom process and accounts for it in the meter reading. This would be analgous to bellows extenstion compensation in LF. So I would at least double check this before feeling confident your Eos readings will carry over to LF.

 

Every meter seems to have its pros and cons. The ol Pentax spot is big and bulky, but very accurate and the manual dial is actually a very desireable feature. Your chances of making a mistake are less. Plus you can see every combination of ss and f stop with out moving anything. The new Pentax spot is much smaller and also very accurate, but lacks the big wheel.

 

I have used just about every type of meter while shooting landscapes. (I am assuming this was your purpose) Other posters have pointed out the usefulness of an incident meter. I totally agree with them, it gives you the true reading of the light source, not the reflected light which is the purpose of a spot meter. However, if you had a choice of one or the other for landscapes, a spot meter is mandatory for the simple reason you are not always standing in the same light your scene has.

 

The ultimate is one meter that has both. Of course carrying two meters if they are not too bulky is a good idea also in case one goes dead on ya. The New Digisix from gossen is a very small incident meter that can make a good adjunct to a spot meter.

 

If your choosing between the Sekonic 508 and 608, the 608's ability to veiw the readings in the view finder is invaluable when your working fast. I also have the Sekonic 778, a great spot meter, but a tad big. But all these are small in comparison to carrying an EOS body and lens. Unless of course you plan to bring the camera anyway.

I investigated Robs comments about DOF being 1/3, 2/3 in front of and behind the psf. After further review of the standard DOF formula, I made an interesting disovery that I never realized before.

 

Both myself and Rob were right about this! It's amazing how tricky and deceving these formulas can be unless you run them.... the bottom line is, at closer distances, the split is almost exactly 50/50, (DOF in front of psf / DOF behind psf) yet at further focus distances the split move is dramatically altered, such as 10/90 ! Here is two examples.....

 

Depth of field (non macro)

 

150 focal length mm, f11, 0.0333 cc mm, 10 ft - focus distance

 

114.3 " DOF Near, 126.3 " DOF far

 

11.9 inches total DOF

 

48% In front of focus distance (psf)

 

52% Behind focus distance (psf)

 

So focussing at 10 ft (definetly not macro) the DOF split is almost

exactly 50/50

 

 

Now lets focus at 150 ft.

 

150mm fl, f11, 0.0333 mm cc, 150 ft focus distance

 

86.0 ft DOF N, 586.7 DOF F

 

500.7 DOF ft total

 

13% In front of focus distance (psf)

 

87% Behind focus distance (psf)

 

Focussing at 150 ft, the DOF split is close to 10/90! (even way more than 1/3, 2/3) So bottom line, based on the variables in the DOF formula, I have found the DOF in front of the "point of exact focus" can vary from .1% to 50%, while the DOF behind the "point of exact focus" can vary from 50% to 99.9%!

 

So there is no fixed % of DOF in front of or behind the point of exact focus (psf).

Sorry this part got garbled in the post....

 

177.6 inches near DOF to maintain desired cc

 

180.0 Inches, point of exact focus.

 

182.5 inches, far DOF to maintain desired cc

Robert, thanks for the correction of focus plane at the film plane.... I did not catch my error on my proofread.... also, you wrote...

 

If by DOF you are referring to Depth of Field, may I point out that this zone is twice as deep behind the object plane as it is in front of that plane. Only with certain very special lens designs does this change

 

Here is the standard DOF calcs for a 15 ft focus distance using the variables above, 150 focal length, f2, .0333 mm cc, 15ft focus distance....

 

177.6 inches near DOF to maintain desired cc

180.0 Inches, point of exact focus.

182.5 inches, far DOF to maintain desired cc

 

This represents 2.5" in front of point of exact focus and 2.4" behind the point of exact focus. This fits the half in front, half behind desciption, vs. "this zone is twice as deep behind the object plane as it is in front of that plane"

 

Were you refering to the Hyperfocal distance where this occurs? I am curious as to your findings.

Hi David, I wrestled with this myselfon a 4 ft toyo rail set up. I assume you are shooting in the field...

 

I have tried dual tripods, but found this very cumbersome, but possible. If you do use dual tripods, I would set them up first putting one single rail between them, then tighten the tripods and heads so they are level with each other with no stress on either tripod.

 

Next, I tried the single tripod in the rear with a monopod in the front, as suggested above. Did this for awhile, but the monopod is not ideal as it only has one fixed point to the ground and the rail can force the monopod to rotate at the ground point.

 

then I tried the Bogen telephoto supports on the front and the back with the tripod in the middle. For me, this was the best compromise between ease of setting up and stability.

 

The tripod Bob S reccomended may be a viable alternative, assuming its arms are strong enough, you can handle the extra weight and bulk of the tripod. Good luck....

Mark, you wrote....Are we talking that say, 2mm of play would have a very noticeable effect on focus? Or would it be more?

 

Using a desireable circle of confusion of .033 mm, the film must be within .0666 mm either in front of, or behind the the plane of sharp focus at the film plane. This is impossible to acheive with standard film holders. Insert a piece of film and see for yourself... 4x5 film is not flat, it buckles in its own special ways. This is one of the reasons LF lenses are optimized at f11 - f32. Anything less would be counter productive. Of course, one method to reduce this part of the problem is using a vacum-back film holder to acheive perfect film flatness.

 

However, if the lens your shooting with is many stops removed from its design MTF range, your limiting factor most likely will be your lenses, not the film flatness. Both issues working against you can be disasterous. Of course I am not making claims about the lens you are using, as I am not familar with it.

 

As many posters mentioned above, all these issues are muted if your gg and film alignment is not highly accurate. Mamiya USA will check this with a laser and adjust it accordingly.

 

I am sure you are familar with the DOF of shooting at f2. Using the same cc as above, focussing a 150mm lens at 15 ft, produces a DOF of 5 inches. (2.5" in front of and 2.5" behind the plane of sharp focus)

 

These are some very tough requirements for shooting 4x5...but I guess if your trying to exploit the full sharpness capability of LF, it would take a very unique lens, a vacum back, a laser verified gg / film alignment and a subject which is either very far away, or extremely flat. Otherwise, IMHO, shooting a good MF camera would produce superior results, even after the 2x enlargement required to compare to 4x5. MF cameras have lenses designed to be shot very wide open, excellent film flatness (specially in cameras like the Mamiay 7), vs. sheet film and excellent gg/film alignment (on most newer MF cameras)

Jorge, Graeme, and all..... Can you imagine in 10 years, many photographers that grew up with PS and never printed in the darkroom... they make digital files, manipulate with software way more powerful than todays versions and make awesome prints at the push of a button..... if they only knew the amazing work people had to do in the darkroom to accomplish the same tasks.... to them, it would seem these these darkroom techniques are outdated by centuries, not a few years. What a revolution this field is going through.... this thread is a stunning example of it.

Scott, you sure walked into a hornets nest with this one! I commend your studious approach to making wise purchases. There is never any harm in asking many questions... of course, sometimes experience is mandatory in making the right decisions. Don't get discouraged by this thread, it appears more people are responding to your tone vs. your issues. Your not the first one to get blasted in this forum!

 

You wrote.... I and any other sensible consumer will be far better off indeed not doing business with any provider who resents questions, analysis and discrimination.

 

I can totally relate to your position on this issue. In a perfect world this would be a great way to do business. However, as you know, the LF world is far from perfect. And it will only get worse...with digital sneaking up on us, you can expect LF lens makers to focus less and less on LF lenses in the future.

 

So the bottom line is..... when you need a lens of a specific focal lenght, you research the market and find which maker has the product that best fits your needs, i.e. performance and price. Unfortunately, you can't always find the same lenses from all the makers in the same fl. So your main focus should be on meeting your needs first, then making your purchase dollars count as a vote in the LF lens industry.

 

As for your comments on hard to find information... Well compared to other industries, I totaly agree with you, but I think you don't realize just how tiny the LF lens market really is. This makes it even harder as companies are not looking to invest dollars into a division that is dealing with such a small and limited market. I may be wrong, but I don't think Nikor or Fuji has introduced a new LF lens in at least 7 - 10 years.... this shows their committment to the market. It's almost impossible to speak to a knowledgeable LF lens rep in USA for Nikor or Fuji. Yes it's hard to beleive these two companies can not at least maintain current brochures and make them readily available or copy them and post them on a web site. Seems like a simple fix, huh. But both Nikor and Fuji are in my lens arsenal, why? They make lenses that Schneider and Rodenstock do not make...and I needed those lenses...it's that simple.

 

As for your comments on Schneider, I agree....they clearly have the best web site on LF lenses. Quite impressive indeed. I commend them, and as you can see they continue to produce new LF lenses every year, so they seem to be here for the long haul and you can not go wrong with thier lenses.

 

Rodenstock, in my opinion, is a bit behind Schneider in web site access. Still not sure why HP does not maintain a Rodenstock web site in USA that is easily accessable in English and contains all the revelevant data. But maybe they will in the future. HP is very responsive in sending out marketing literature, even if you are one of the many who have engaged in war in these forums with Bob S. (trust me, I know) Their brochures are very thorough.

 

Anyway, good luck in your venture and be careful not to loose sight of what is most important - you get lenses that best fit your needs, i.e. price and performance. I doubt the designation of your dollars will have any impact on the LF lens makers. IF your unsure after reading the brochures, then post some questions about those specific lenses. Experience in the field is invaluable....and that is the beauty of forums like this, you can call upon many experienced users that you ordinarily would have no access to in your community, so take advantage of it. Hope this helps...

I refused to buy teles for years as I was nervous over the loosing resolution. Then when I moved up to 800 and 1200mm, I had no choice but use teles. Some of my 1200 shots are the sharpest shots I ever made, and this includes stiff competition from my other lenses, such as the Fuji 240A, 110 & 150 Super Symar Xl's. I can't speak for all tele lenses, but I have great luck with the 800 and 1200 Nikors.

Jorge, I trying to figure out how you can make two exposures and register them, then print on an enlarger? I can see how this will save blown out highlights, but it will make the shadows much worse? How do you salvage the super plugged shadows? When you expose for the highlights, you stop down....making the shadow super dark one piece of film and dark on the other...to make matters worse, you then have to pass light through two sheets of these plugged shadows? What am I missing? Sounds like you must be doing something else such as masking?

I understand the Fuji 6x17 GX camera has a solenoid that fires the

shutter. I have never seen this rig, I have a few questions.

 

1. What is the benefit of this? Less camera shake vs. cable release?

 

 

2. Does each lens come with its own solenoid? Or is the solenoid part

of the camera body?

 

 

3. Is the solenoid permanetly affixed to the lens?

 

 

4. I assume these can be adapted to any new LF lens?

 

 

Thank you all in advance.

I understand the Fuji 6x17 GX camera has a solenoid that fires the

shutter. I have never seen this rig, I have a few questions.

 

1. What is the benefit of this? Less camera shake vs. cable release?

 

2. Does each lens come with its own solenoid? Or is the solenoid

part of the camera body?

 

3. Is the solenoid permanetly affixed to the lens?

 

4. I assume these can be adapted to any new LF lens?

 

Thank you all in advance.

Hi Paul... as you probably know, there has been some good threads on this in the past. I use the Calumet tester and its amazingly accurate considering its cost. I tested 13 LF lenses, 4 Mamiya lenses at all shutterspeeds...the worst one I found was off by 1/3 stop...the rest were within +/- 3% on average. The conclusion of my study was, most newer shutters are amazingly accurate... I have never tested more vintage shutters.

 

However, as I mentioned in the previous thread on this subject, the real variable with exposure is light meters. But very few people want to focus on these gems. A simple check of a meters linearity, is to put the meter in front of the gg and cover to protect from light. Then point lens at bright wall.... start with apt wide open, take EV reading....then close down apt one f stop, check light meter reading.... all EV readings should be one stop apart. I tested 5 light meters, including the newest Sekonic 608, and all were terribly off at either the high end, low end or both ends! Instead of finding shutter speeds being off, I was suffering from the meters being off 1 - 2 stops at different parts of the EV scale. Change light intensity to cover the full EV range of the meter.

 

Of course this identifies the problem well, but does not provide enough data for corrections. In my case, my meters all read the same in the mid EV range, such as 8 - 10. In which case, I concluded from experience, I had no exposure problems in that range, so I made corrections for each meter based on the 8 - 10 EV range being accurate. If I did not have several meters all reading the same in the mid range, I am not sure how I would have tackled this. My point is, the meter is just as important as the shutter speeds.

 

I had read several articles on how far off shutter speeds are on different cameras...this lead to my desire to test. It never hurts to be too safe.

Ralph, the problem with Polaroids or loupes on the gg is you can not get enough resolution on either to determine what you are looking for. This issue would require very high magnification to before its exploited enough to be visible, my guess is 8x +. A ground glass can barely resolve 2x - 4x based on the type of gg, a polaroid even less. Unless maybe you use the Polaroid B&W negatives..but even then, I would have to question how accurate the film flatness would be vs. film in a film holder.

 

Leonoard, this is a very interesting question.... and I am glad to have read Struans response before commenting :-) I have to admit, I don't fully grasp what he wrote... I follow his concept but just can't visualize the circle on the film when the lens is tilted. But when Struan talks, I always read with great interest!

 

Possibly the question can be asked a different way, and maybe this will solicit some new thinking. When the front lens is tilted forward, the top of the lens is further from the film plane than the bottom of the lens. I have never seen this addressed in DOF equations for tilt. Tilt DOF, even in Merklingers book, assumes the same DOF near and far limits as for non tilted lenses, assuming you are focussed at the hyperfocal distance. But I now find this hard to accept considering that the upper part of the lens is closer to the film than the bottom part. In extreme tilt, 35 deg, there difference is huge.

 

I would propose this test to find out if there is merit to this. My common sense tells me there is, but I have been fooled by common sense in the past. Using Standard DOF tables and a given cc size, focus at some distance, notice the near and far DOf limits to maintain this cc. At the near and far limits put a stick in the ground that has some fine lines of different dimensions, like a home made lens chart, but for far distances... take image with sharp B&W film.

 

Next, using the same lens and film, determine the tilt angle and f stop to match the exact same DOF near and far limit. (If you need help with this, I can email you a jpeg of such - it will show the exact same DOF near and far limits for both tilted and non tilted lens) Shoot the same image using tilt and the same f stop.

 

Now, if Merklinger and Struan are correct (I think Struan was supporting this) then you should be able to read the exact same detail at the same magnification on the charts in both the tilted and non tilted shot. If lens tilt causes different size circles due to the changing distance between lens and film througout the tilted glass, or the lens does produce eliptics vs. cirlces, this experiment would demonstrate such on the film in a very obvious way. If there is a major difference in the two shots, I think you might have opened Pandoras box on this one. Its possible this has been something over looked in years of photography? It would not surprise me, as lens tilt has been very slowly pioneered through the years.

 

To be sure the test is accurate, I would reccomend you use an f stop whithin the MTF of the lens, you use a lens with a very large image circle so you can maximize the tilt angle to exaggerate the problem if it exist and you make sure there zero wind when you test this. The large image circle would also assure you any loss of detail is not coming from the outer edge of the image circle where the resolution is much less. Use 8x10 lenses with roll film, it should avoid this potential problem. I would be very curious as to your results.

 

Sorry I did not have a good answer for ya, but sometimes good questions just raise new questions! :-)

N...about this gasket idea.... have you done this before? Have you actually noticed less vibration on the film after employing this technique? It sure makes a lot of sense, I am wondering why the lens makers don't provide these?

 

Also, as for shutter vibration, are the new Copal shutters more vibration proof vs. some of the older shutters? I imagine this has been one of the improvements in shutter design through the years.

 

Paul Schillinger posted an excellent test to help determine the amount of vibration when firing the shutter. He proposed using a tiny strand of wire, a single strand found inside a normal lamp cord. Take 8" piece and tape on the lens front, projecting out towards subject. Fire shutter and watch the wire vibrate. A bit unscientific but an excellent reference point to compare lenses / cameras. It would be interesting to read peoples results of such.

Paul, be careful if you are considering buying a used 80 SSXL. The initial batch of them were recalled. You may remember on this board some complaints about their sharpness vs. the 110 and 150 XL's. Schenider recalled all the initial lenses as there was a manufacturing defect causing this problem. So be sure if you go used, you get one that has been factory corrected.

lots of conflicting information here... Clyde, are you saying the 6x17 back slides in just like a 5x7 film holder? If so, it should fit every 5x7 camera. Unless most cameras can't accept such a fat "film holder". Hence the reason there needs to be another way to attach the 6x17 holder to the camera. I think that's why Kieth mentioned you have to remove the gg and affix it to the camera through other means...?

George, I did not know this... very interesting. I thought you all were referring to the nodal point being just forward, but not actually in front of the lens. Now I better understand Jonathans points...now it makes sense, the Nodal point being at a distance equal to the fl, from the film. This also perfectly explains the normal jumps in bellows compensation after infinity, just like normal lenses. I think we all got educated on this one! I wish Struan Grey was still on this list, he was a real optics guru.

Johathan.... you wrote...I know that the nodal point is ahead of a telephoto, because I've read some literature on this, but in regards to my Tele-Arton, I don't know specific numbers about how much, but now that my curiosity has been piqued by this, so I of course intend to find out.

 

OK, now you are provoking my curiosity! Are you suggesting the lens nodal point is not contained within the confines of the lens? Are you suggesting the nodal point is actually in mid air in front of the lens? If so, that is pretty amazing, but I doubt it's true. (but I would like to be educated on this myself) The nodal point is actually caused by the glass, which therefore would place itself inside the confines of the lens. Or are you referring to the nodal point just being further forward vs. normal lenses?

 

> Certainly I'd be in violation if I never/seldom/didn't test, but my wife complains that I test too much, I verified/checked/confirmed the results of the first cheat sheet I did on my other lenses the way you suggested, so it was never my blanket suggestion that you don't have to test.

 

Isn't it amazing that the one thing you don't test is the one that bites you in the ass! Don't worry, I get hammered all the time by people screaming at me for testing, testing, testing. It does get boring. But some tests, such as seeing how far off my spot meters are at different stops, well it was truly mind boggling.

 

> You still gotta a beer coming, I'm going to get mine, and have a little toast to a little more understanding of teles

 

count me in! BTW, I used to read a lot of bad press on teles sharpness. However, I am overwhelmed with the sharpness of the Nikor teles, 600, 800, 1200. How is the sharpness of you 270 mm tele?

From my discussions with Keith, the 6x17 back is NOT graflock! hence the reason, right now it only fits his MCQ5x7. Graflock dies after 4x5. How many 8x10 cameras are graflock?

 

I asked if it would fit an ARCA 5x7 I am strongly considering purchasing. He advised me ARCA will be making a new standard to accomodate his 6x17 back. But then again, they will design it when someone orders it, so who knows how long all this will take. Its hard to beleive in this digital era that a film product can be waited with such anticipation! Maybe film is not dead? :-)