mamiya 645 lenses vs 'blad

[andy_buck1]

<p>I am considering buying a Hulcherama 360 camera. It takes either Mamiya 645 lenses or Hasselblad lenses. In the 50mm and 80mm ranges which do people think would be sharper? The obvious guess would be Hasselblad, i.e. Zeiss, but the Mamiya lenses are for smaller format, i.e. less coverage, so theoretically could be sharper. I would use 50mm 'blad or 55mm Mamiya more often than 80s.</p>

<p>Thanks.</p>

<p>Andy</p>

[michael_dimarzio]

<p>I used a M645 with ULD glass, and the 80. I have a 500c/m with a 80 CF. I don't think either would be non sharp. My experience says 7 out of 15 shots would be sharper with Zeiss. More important would be the condition of the individual lens that you buy, regardless of the name on it.</p>

<p>Andy, here is something that doens't make sense to me. Regardless wether 645 or 66, a lens has to cover 6cm. Since 645 lenses don't project a square image, they still need to cover 6cm on one axis, I don't think that a 645 lens projects a smaller image, or in theory would be a smaller format as far as optics go.</p>

<p>Anyone want to expound?</p>

[Aoresteen]

<p>Mike you assume that the 645 lens is ground in a circle with all points within specs. That's not trure and an 80 lens that wouls faill testing for 6x6 can pass coverining 645.</p>

<p>I use Hasselblad and Mamiya 654 glass - the only limit is me.</p>

[michael_dimarzio]

<p>Thanks Anthony.</p>

[tomscott]

<blockquote>

<p>Mike you assume that the 645 lens is ground in a circle with all points within specs. That's not trure and an 80 lens that wouls faill testing for 6x6 can pass coverining 645.</p>

</blockquote>

<p>Michael, I am with you on this one, how could a lens not be ground in a circle with all points within specs? If it weren't seems like you wouldn't be able focus. Can anyone clarify this for me, I just bought a 645 and would have assumed the lenses would be the same as 6X6, 6X7 or 6X9?</p>

[ivan_shukster1]

<p>Draw a retangle for each of the formats you want and draw a circle to cover the entire rectangle. The size of the circles are not the same regardless that one side of the rectangles are. A 645 lens does not have to be able to cover a 6X6 and certainly would not a 6X9. To calculate the circle of coverage needed square two adjacent sides add the results and find the square root.</p>

<p>Take a look at the diffences in sizes between Pentax 645 and 67 lenses or Mamiya 645 and 67 lenses, those companies would not make one set of lenses much larger than the other if both covered the entire film area.</p>

[tomscott]

<p>Maybe I'm just tired but, if you draw a rectangle 6cm x 4.5cm and then drew a circle to cover the entire rectangle, would the circle not have to be 6cm in diameter, and then would that not mean that it would take the same size circle to cover the square format of 6x6? Don't get me wrong, I am sure what you're saying is correct, it's just not sinking in.</p>

[q.g._de_bakker]

<p>The image circle has to be wide enough to cover the longest line you can draw across the frame, i.e. the diagonal. And no wider.<br />Then it's simple maths: the diagonal of 6x4.5 is covered by a circle of 70 mm in diameter. 6x6 requires a circle of 79.2 mm.<br />So no, 6x4.5 lenses are not 6x6 lenses.</p>

<p>Lenses are designed to cover a format, and made within specification. No manufacturer makes lenses to let sloppy work decide what format it can cover 'within specification'. No 6x4.5 lens is a 6x6 lens that did not make the grade.<br />Though yes, some manufacturers have poor quality control. But they also do not decide that, if a lens isn't good enough for a larger format, it will do fine on a smaller format. They just sell bad lenses.</p>

<p>Mamiya lenses are generally great. But those of the 645 are clearly less so (it is quite noticeable that Mamiya had a cheap entry level and a more expensive professional level.)<br>

Zeiss/Hasselblad lenses are beter.</p>

[jack_welsh]

<p>Hasselblad lenses might be better. But, even though the prices have come down. They sure are expensive. Keh has Excellent 80 mm ones for between $450.00 to over a thousand.</p>

[steve m smith]

<blockquote>

<p>Maybe I'm just tired but, if you draw a rectangle 6cm x 4.5cm and then drew a circle to cover the entire rectangle, would the circle not have to be 6cm in diameter, and then would that not mean that it would take the same size circle to cover the square format of 6x6?</p>

</blockquote>

<p>No. Draw a rectangle to suit the format size. draw two diagonal lines between the rectangles corners. Where they intersect is the centre of the circle. The distance between the centre and one of the corners is the circle's radius.</p>

<p>Even easier, the diameter of the circle is equal to the length of one of the diagonal lines. i.e. from one corner to the diagonally opposite corner.</p>

<p>You can try it the old fashioned way using a pencil and pair of compasses or if you have access to CAD, that makes it easier to compare.</p>

<p> </p>

[tomscott]

<p>It all starts to make sense now that I've had a nights sleep, and someone throws in the word diagonal. I actually thought about that last night because of 35mm being 24x36 in actuall size and 35mm is the diagonal but being tired, I quess I still didn't put it together. Thanks for clearing that up for me and, sorry if I took over the thread.</p>

[q.g._de_bakker]

<blockquote>

<p> I actually thought about that last night because of 35mm being 24x36 in actuall size and 35mm is the diagonal but being tired, I quess I still didn't put it together.</p>

</blockquote>

<p>You still haven't. ;-)<br>

The diagonal of 24x36 mm format is a bit more than 43 mm. Not 35 mm.</p>

<p>35 mm film is called that because in 1891 a man called William Dickson split a roll of film 70 mm wide down the middle (the film was to be used in the Kinetograph camera).</p>

 

[tomscott]

<p>You know the bad part is that I actuall knew that the diagonal of 24x36 was around 43mm, thats is why a 45- 50mm lens is considered as a "normal" lens. I'm just not thinking straight. Or not putting my thoughts into words properly. Thanks again for straightening me out. The mind is a terrible thing.</p>

[rodeo_joe1]

<p>Andy, how big are you considering printing your panoramas? Because the aspect ratio of these pictures is 4.3:1 - which means that a picture 26 inches long is only going to be 6 inches high. Now it's almost impossible to see any difference in quality between any two halfway-decent lenses on what is effectively a six inch print, so debating the finer points of optical quality might be completely irrelevant. Unless you're planning on producing prints a couple of yards long. Plus the size of the slit used in the pano camera will make the corner quality of any lens used pretty much a non-issue. I'm guessing that only a few millimetres wide slice from the centre of the image circle is used.</p>

<p>Also, have you considered the availability of the 45mm Mamiya lens? Since I believe that Zeiss don't offer anything between 50mm and 40mm. Actually, I'm not too sure how the focal length affects this sort of panoramic picture. The horizontal angle is always going to be ~ 360 degrees, but the vertical angle will vary with the focal length used, which might give a foreground and sky heavy result if the lens is too short - I think. Correct me if I'm wrong here.</p>

[andy_buck1]

<p>Thanks for the related answers. As usual, lots of wandering topic answers, the nature of this beast. (And sorry for the delay. I had to go out of town for a few days.)<br /> <br /> First, lenses on a rotational or swing-lens panorama using 120 film only need to cover 56mm, the width of the exposed area of the film. So, any medium format lens will easily provide coverage.<br /> <br /> Rodeo Joe: I should have said how big I was going to make the enlargements. They will be enlarged at most 8x and probably only 6x, i.e. a 76” long print with a 50mm lens is a 6.15x enlargement for 360 degrees and with an 80mm lens is a 6.28x enlargement for 220 degrees, my two biggest plans. Slit size will be ~1/8”, a good compromise sharpness wise. <br /> <br /> Thanks again!</p>