paul_loveteck

<p>Pengtao,<br>

No, don't worry. It is often the case that such systems do not sell the first time they are listed. The market for such system is small and the right buyer is not always on eBay at the right time.<br>

You ARE protected by eBay, believe me, and their protection for the buyers is very strong. In fact, most sellers are complaining to eBay regarding their policies on that matter.</p>

<p>Pengtao,<br>

After looking at it, if I was you I would buy it.<br>

Contrary to what QG says, you are fully protected by eBay if the seller lies on his listing, so, at most, you will waste some time and lose your S/H to return the camera.<br>

$2,500 is a very decent price for this camera, go for it!<br>

Tell us when you receive it.</p>

<p>Pengtao,<br>

Looking at a link outside *Bay is dangerous, specially when there is no return. *Bay will protect you ONLY for the description and images you see on their site. The outside images can disappear as soon as you pay . . .<br>

The images look like it is a nice camera, worth the $2,500. However, I looked on *Bay and could not find this camera. Can you give us the item number, I will look at how the seller describes it and at the ONLY images on which you can rely.<br>

KEH is very difficult as they do not give you any information on the 503CW's. For example, you cannot know if the camera is the ISO 3200 version (the one to buy) or older much less desirable cameras (ISO 800 or 1600). Yes, you can return it to them, but you pay the S/H and waste weeks.<br>

Finally, yes, the 503CW is the best in MF. Better than the more expensive 203's, 205's . . .</p>

<p>Yiannis,<br>

How many C lenses did you try? (only one or more)<br>

How many CF lenses did you try?<br>

Your answer would help us to give you an idea as the problem might be a lens or the camera.<br>

(C lenses being older, one might have an easier, well used, trigger mechanism for the camera to operate and work when a newer CF might be still be stiff enough that the camera spring is too weak to operate correctly . . .)<br>

Also, be sure that your CF lens is not in the "F" position.</p>

<p>Yes, it will fit your 501C.<br>

However, $175.00 seems to be low for a 42170 in good condition.<br>

Be sure it is a real one, ask for picture and if any marks or scratches.<br>

They cannot be cleaned with any liquid without being ruined.<br>

It should be divided in 6 rows and 6 columns by a grid and have a split-image at the center.<br>

Split image should NOT be at 45 degrees.</p>

<p>Jon,<br>

Before changing your screen, you might also consider using a prism as they enlarge the image (2.5 to 3 times depending of the prism) and certainly improve a lot focusing speed and accuracy.<br>

Regarding screens, the choices are somewhat subjective. I have tried them all, and the one I prefer are definitively the Acute Matte's. I specially like the 42215, the 42170 (or the identical 42217). They provide not only easier focusing in low light (or with long lenses with limited aperture) but more accurate focusing, specially when used with a prism. The 42165 (or identical 42204) has no split-image but is also a good choice.<br>

Be sure you do not buy a 45 degree split image: they are junk Russian or Chinese copies.<br>

If you buy on eBay, insist to see an image of the screen, not the box. Many sellers have boxes containing the (poor) screen they replaced, not the one they pretend selling. Good screens are expensive, if you get one for $25 you will get the quality . . . you paid for!</p>

<p>When i feel it's time for playfulness shooting session requiring a quiet shutter, relatively small size and quick action, i take my Leica M3 or (shame . . .) my Nikon D3. I would think of using my chain saw to cut my bread before thinking of using my SWC for shooting playfulness actions!<br>

When it is time for landscapes, I used to take my SWC. I now take my 503CW (a 500C/M would do as well) and my 40mm CFE IF. It has only one focusing ring, is sharper than the Biogon 38mm and produces amazing pictures. But, the main reason I prefer this setting is composition, not the lens. I had never been able to compose with a SWC as well as with a 500.The weight and size differences are then almost irrelevant as I use a tripod anyway.<br>

This is of course subjective, but for me composition and light are the most important things in landscapes and my 40mm CFE IF beats the SWC everyday. For the same reasons, I would also take a 500 with a 40mm CFE FLE in the field instead of my SWC.<br>

Some will say that the 40mm CFE IF has slightly more distortion than the 38mm Biogon. This is true but it is automatically corrected by the (free) Hasselblad Phocus program and, in general, is not a problem in landscapes.<br>

I loved my SWC, it's a beautiful piece of hardware, but mine now is for display only.</p>

 

<p>Ivan,<br>

Quite an interesting puzzle!<br>

I have never seen this before.<br>

Your suggestions:<br>

1- I do not think the clips are bent. They do not seem to be on your Youtube video and you would probably notice it easily.<br>

2 - On your picture, the frame looks OK. Most Hasselblad screens look like this at that kind of enlargement. Before looking at your Youtube, I thought your screen was probably a cheap Russian or Chinese screen, but it really look genuine.<br>

3 - The screws you see cannot change the position of the screen. They only keep the top of the frame on the inside main frame (the camera has an outside shell and a complete inside frame which holds the mechanism).<br>

The possible adjustments of the inside frame (which supports the screen) relative to the outside shell are done with a few screws located in the front of the camera (hidden under the leatherette) and in the bottom of the camera. Using them, you can adjust the relative positions of the outside and inside frames. Although I have never seen it happen, I guess there is a possibility that the two frames are at a bad angle, making the screen loose.<br>

Please, check the back of the camera: the inside frame (the Black metal plate) should be absolutely flush with the camera shell (the thin outside metal shell surrounding the plate). If not, they need to be adjusted and . . . your screen won't move again.<br>

Keep us informed of what you find!</p>

<p>Ken,<br>

I believe you deserve a statue for this post!<br>

Do you prefer marble or bronze?<br>

I suggest to name it "Ken, The Lord of the Bellows" unless somebody has a better idea.</p>

<p>I would <strong>never</strong> buy something on eBay if the serial number(s) is not clearly stated or if the seller does not answer when I ask for it.<br>

As far as Hasselblad backs are concerned, you can be 99.99% sure that if the seller does not say that the numbers are matching they do not match.<br>

If the seller does not know what you are talking about, be ready to send your back to David Odess when you receive it!</p>

<p><a href="../photodb/user?user_id=2342830">Michael Bisset</a> ,<a href="../photodb/user?user_id=1713391">Michael Axel</a>,<br>

As you did not specify which 50mm you own, the weight and size are difficult to judge. My favorite version of the 50mm is the CF, not FLE, it has only one focusing ring (a big advantage), is smaller than the 80mm and weight almost the same as the 80mm. It is very sharp, and except in few situations you will not see a difference in image quality with the FLE.<br>

If this is the one you own, I would definitively recommend that you take it in your trip!<br>

Regarding film, if I had only one to take, I would go with Velvia 50. (A highly subjective choice!)</p>

<p>Michael,<br>

This is a highly subjective question as it really depends of your own style.<br>

Let me give you my (highly biased!) answer as I often face the same dilemma:<br>

- Take the 50mm<br>

- Don't take the D300 unless you plan to sail on the SF Bay and you need an extra anchor<br>

- Replace the D300 by the 150mm<br>

- Use a metered prism and leave your light-meter home. Be sure you use it before so you know it. Best choice is PME51.<br>

- If you really want another second camera, buy a cheap tiny Canon. It will do most of what the D300 would do and take no extra space.<br>

For whatever it is worth for you, after years of trials, when I travel and can't carry too much, I take my 503CW with a 40mm CFE IF and a 100mm CF. They are both so sharp that you can "extend" their use outside their format and cover a wider range. But, again, this is my personal choice and won't necessarily fit others.</p>

<p>Q.G.<br>

One more time, I am asking you to stop misleading readers on this forum.<br>

You say: "Adjusting frame spacing is a simple job", that simply is NOT TRUE. It might be for an Hasselblad technician, not for anybody else.<br>

Then you say "often all is needed is to tighten screws". This statement is not only not true but absurd.<br>

Then ". . .replacing a nylon part that takes a 'pounding' each time you wind on". Another absurd statement. I suppose you are talking about the nylon stop. This part has nothing to do with spacing.<br>

Another thing you say: "...it's either an adjustment" is not true most of the time as the only adjustment possible is rarely the culprit and, when it is, adjusting the dial wheel to the correct position is not easy.<br>

In addition, simply finding where the problem really comes from can be very difficult and most technicians will prefer to simply change all involved parts as this will not require wasting the time to find the exact problem. The parts involved are few and well known by knowledgeable people (the one not trying again and again to mislead on this forum).</p>

<p>Q.G. is wrong on all his statements and will never even try to justify them, preferring to insult whoever is contradicting him.<br>

As clearly shown by the formula I gave earlier (which Q.G. is unable to understand), even at constant magnification dof is STILL function of the distance.<br>

In addition, as everybody knows, if you want to compare two objects in relation of a parameter, you keep ALL other parameters identical. The subject of this discussion was to compare the dof of two lenses in function of their focal lengths. The only (intelligent) way to do this is to keep all other parameters IDENTICAL, this implies d (the distance, which also implies NO CROPPING), the aperture, the circle of confusion etc . . . must remain the same.<br>

Changing the distance (or what is equivalent, cropping or the magnification) on one lens is idiotic. It would be the same mistake to change the aperture, like having one lens set at 2.8 and the other at 32 and use the result to compare their dof's. BOTH the distance AND the aperture are parameters of the dof in the definition of the dof. You CANNOT change either of them to compare the dof of two lenses in function of their focal. But the lack of education of Q.G. (also apparent in his insulting answers) makes him unable to understand this.<br>

As Jeff correctly points out, even at constant magnification (which is not a correct way to compare two lenses), dof is still a function of the distance, even if it is to a lesser degree.<br>

Some people believe the earth was created 4,000 years ago, climate change does not exist, Darwin was wrong and the sun runs around the earth (or around themselves in Q.G.'s case). It is sad they post on this site and mislead fellow photographers.</p>

<p>Q.G.<br>

From your own posting, February 13,2012 which everybody can verify:<br>

"Shorter lenses do not have more DoF. And you would need more depth of focus, not depth of field."<br>

I will stop answering to you when you stop misleading people with ridiculous information.<br>

I continue to think that you buy those barrels to re-engrave them to fit your pseudo dof data.</p>

 

<p>Richard,<br>

You got it wrong!<br>

The answer is simpler: <a href="../photodb/user?user_id=282122">Q.G. de Bakker</a> is buying all wide angle lenses to correct the mistakes made by the Zeiss engineers. He will change their barrels with re-engraved ones where the DOF scale will be identical for all lenses.<br>

His many posts show that he is a believer than all lenses have same dof and Zeiss, Leitz, Nikon and other Canon engineers were all wrong . . .</p>

<p>Q.G.<br>

The only thing fuzzy is your brain.<br>

Like most people who do not understand science or mathematics you try to refute them with empty critics not worth the web space on which you post them.<br>

You asked me a few questions to which I precisely answered and either you did not reply or did it with incoherent ramblings.<br>

If DOF was a fuzzy concept, as you say, the Hubble telescope or Zeiss lenses would not exist. DOF has been defined by scientists, not by illiterate.<br>

Finally, yes, one of the goals of science is to reduce complex phenomenons into succinct yet powerful definitions / equations which can then be used to make progress possible. DOF is a good example of this, but you will never understand that concept of simplifying in order to allow progress as this requires a non-fuzzy brain.<br>

Behind a simple equation which can represent extremely complex systems with a few symbols (the ultimate form of compression) you always find a great (non-fuzzy) brain.<br>

If those scientists had not existed, we would still live in caves and you would be happy as nobody would contradict you.</p>

<p>Q.G.<br>

Thank you for the interesting last link.<br>

To answer your question, it is very easy: you take a camera, a tripod and the two lenses you want to compare for their DOF. You mount the first lens and be sure to use an f stop also available on the other lens. You set the focus on one object and take the picture.<br>

You then replace the lens by the second lens, keeping the tripod at the same place, set the same aperture and focus on the same object (which should still be at the same distance).<br>

You take your second picture.<br>

You will then clearly (believe me) see which lens has a greater DOF. DOF has nothing to do with magnification and trying to artificially make the two objects the same size results in comparing two unrelated things, not the respective DOF's<br>

Roughly speaking, DOF is the distance between the front and remote objects which are "in focus", at least according to the technical definition involving circles of confusion. DOF DOES NOT imply in any accepted technical definitions (the only making sense as clearly stated) that the object on which you focus be of the same size on both images or be seen in the same perspective. Perspective and/or size do not appear in any serious definition of DOF, definitions lens and telescope manufacturers have been using for decades.<br>

If you measure DOF correctly, you will find (surprise!) that it agrees with the calculation starting from the math.<br>

If you want to measure which of a Ferrari or a Chevrolet has the maximum speed (another mathematically defined term), you put them on the same place for the run. What you suggest is to have the Chevrolet running on a straight line in the Salt Lake area and then the Ferrari run on an icy mountain road and, after your measurement, claim that the Chevrolet goes as fast as the Ferrari . . .</p>

 

<p>Christopher,<br>

Thank you for taking the time to prepare and post your pictures.<br>

I have a comment on your post:<br>

As I have said earlier, if you want to really compare the DOF of two lenses in relation of their focal length, it is important to keep all the other parameters identical as otherwise you do not really compare the DOF of two different focal lengths but something else (which might be also interesting, but it is not the point).<br>

In particular, you need to be sure that the apertures are the same as well as the camera at the same place. And, no cropping! When you crop, it is equivalent of changing the magnification and then, again, you no longer compare the DOF but something else.<br>

This is because both the aperture and the distance (related to magnification) are part of the equations defining the DOF. Changing two parameters at the same time (for example distance and focal length) cannot tell you the difference of DOF between the two lenses! By changing two (or more) parameters, you can easily show that the DOF of a 40mm is smaller or greater than a 500mm or whatever you want. Or prove that the sun goes around the earth! This is what the web site mentioned by Q.G. does and what he believes. . .<br>

If you really want to compare the DOF of two lenses related to their focal length, ONLY f (the focal length) must change.<br>

If you want to compare something else, it should not be called DOF as DOF has a precise definition. That definition has been very helpful for lens designers and photographers who understand it during the past hundred years, which is the reason it was created.</p>

<p>By now, we know that Q.G. does not have the minimum math background to understand what DOF is (it is a mathematical definition): He questions equations because they contain twice a variable, rejects formula because they were developed hundred years ago and/or because they are in old books. He calls DOF a "monstrosity". He also questions the validity of basic science principles.<br>

Well, these hundred years old formula are indeed in old books and are the same which have been used to make the Hubble telescope and the Zeiss lenses. They also are the formula used by all lens manufacturers to engrave the DOF scales on their lenses (when they have one, like the Zeiss or Leitz lenses). They are also the equations used by Nikon and Canon in the embedded software for their auto-focus mechanisms.<br>

All the equations match what photographers intuitively know: when everything else is the same a wide angle lens has more depth of field than a tele lens.<br>

Lack of education is forgivable, lack of recognizing it is not.</p>

 

<p>Ray,<br>

Your point is (I hope) well understood by any photographer.<br>

The disagreement happens when somebody (like Q.G.) does not understand the basic principles of science. DOF is a scientific term, well defined and understood for 100+ years.<br>

When you want to seriously compare an attribute (like DOF) of two things (like two lenses of different focal lengths), you keep all other parameters identical and ONLY change the object of your comparison (the lens or the focal length of the lens if it's a variable focal). You DO NOT change the distance or other factors. This is one of the first thing you should learn in science classes and one of the fundamental principles of science.<br>

Not only changing other parameters make your comparison worthless but it's easy to show examples where by doing it you can prove whatever idiotic thing you want (like the sun rotates around the earth or the DOF of a 40mm lens is the same as the one of a 180mm lens . . .)<br>

The use of a scientific term like DOF requires that you follow the science principles. If (like Q.G.) you do not like what science has to say, it is OK, but then DO NOT use scientific terms you do not understand.</p>

<p>Q.G.<br>

Focal length appears twice because it is the result of the math. In fact, there is a more precise equation (my first equation,as noted, is an approximation) in which it appears 6 times. So what's your problem with it? If you need a course in math, ask me: my fees are very reasonable.<br>

When you say "focal length does not matter, but magnification does", this is your subjective opinion, unrelated to the facts I prefer to discuss.<br>

My first post to which you answered with your unrelated comments on magnification had a precise meaning and still stands.<br>

DOF is related to focal length, and, one more time, I recommend that when you answer a post you do not criticize it without a careful understanding of the subject and of what the author of the post said (like Leigh and me) instead of what you believe they meant.</p>

<p>Q.G. is wrong, once again. There is no misconception.<br>

The formula giving the DOF in function of the magnification (m) is:</p>

<dl><dd><img src="http://upload.wikimedia.org/wikipedia/en/math/3/6/3/363058a841733a87056efe3ca9efdc68.png" alt="\mathrm {DOF} = \frac {2 N c \left ( m + 1 \right )} {m^2 - \left ( \frac {N c} {f} \right )^2} \,. " /></dd><dd><br /></dd><dd>This formula is easily derived from the first formula I gave in this post.<br /></dd><dd>It also clearly shows that the DOF is a function of f.</dd><dd>Only when the distance becomes small compared to the hyperfocale the DOF for a given magnification is relatively independent of f.</dd><dd><br /></dd><dd>In the general case, whenever somebody talks about DOF, the magnification IS NOT IMPLIED to be the same and the DOF is HUGELY depending on the focal length f (as proved by the equations and as well known by any photographer . . .)</dd><dd>The misconception resides only in the minds of people who do not understand math and definition of words. There is no misconception in science. </dd><dd><br /></dd></dl>

<p>The web site mentioned above is written by somebody who does not understand the basic principles of science.<br /> Words like "DOF" are clearly defined before being used by scientists and then adopted around the world. DOF has been defined more than hundred years ago and agreed upon by the international community of scientists.<br /> A crude web site or ignorant people are not going to change that.<br /> With the definition of DOF, it is very clear that <strong>DOF IS A FUNCTION OF THE FOCAL LENGTH</strong> of a lens and, moreover, increases when the focal length diminishes.<br /> Pretending that DOF is not a function of f is like pretending that the sun is revolving around the earth. And, yes, there are still web sites pretending that the sun goes around the earth . . .<br /> In addition, any decent photographer knows very well by instinct that when he is using a 40mm on his Hasselblad almost everything will be in focus with not much effort. He also knows that after switching to a 180mm things won't be so easy. Pretending the opposite certainly does not incline me to give much respect to the author.<br /> DOF is not, like the "respected" author says a matter of controversy. It is a scientific term and, as so, is not open to controversy, no more than saying that triangles have three sides. It is a definition and, as so, is not "good" or "bad" or subject to "controversy".<br /> If the author had any science background he would understand that and, instead of confusing people, publish his own definition of DOF and try to get the international community to change the definition of DOF to his own (which he does not even elaborate . . .). I wish him good luck in doing so . . .</p>

<dl><dd>The formula for DOF is:</dd><dd><br /></dd><dd><br /></dd><dd><img src="http://upload.wikimedia.org/wikipedia/en/math/7/7/d/77d46a8b41790040f6615b2a62a887ee.png" alt="\mathrm {DOF} \approx \frac {2 N c f^2 s^2} {f^4 - N^2 c^2 s^2} \,." /></dd><dd><br /></dd><dd>f is the focal length of the lens.<br /></dd><dd><br /></dd><dd>This clearly shows that Leigh is correct and Q.G. seriously wrong unless he has is own mathematics. The formula also clearly shows that the DOF of a 60mm is greater than a 80mm.</dd><dd>In addition, when Q.G. says " DoF in a given image..." this does not make any sense as an image does not have a DOF.</dd><dd>DOF (Depth Of Field) is a precisely defined term and I recommend to Q.G. to go back to school before attacking serious members like Leigh.<br /></dd><dd><br /></dd></dl>