steve_rasmussen

<p>If you are looking for magnification beyond what the 3 tubes can give, you might need the Auto Bellows that was made for this camera. However you can easily run into diffraction problems when doing so because you are using the lens at longer focal lengths due to the diverging rays entering your lens at macro distances. To focus those rays on the camera's focal plane, added distance is needed via tubes/bellows. You are extending the focus but your diaphragm remains the same, so your focal ratio changes. </p>

<p>Check your meter against a proven meter. </p>

<p>A lot of what you choose depends on what you are used to carrying. Most people will balk at carrying a pack with an array of MF bodies and lenses if they are used to lighter gear. I carry 2 Pentax 67 bodies, both zooms and a 45mm so an RB would not be a stretch for me. Your mileage may vary. </p>

<p>Regarding the Pentax 67 and its weight; a good part of that weight is from the prism finders. If you opt for the lighter finders (rigid magnifying hood or folding focusing hood) you can save some weight. It was primarily designed as a field camera so it does well for landscape work. It has 30 lenses to choose from. </p>

<p>I have had my 67 do this but only when the battery is low(not dead). The shutter speeds become way too fast, thus causing severe under exposure that appear to be blank. </p>

<p>The 165 LS is great for landscapes and macros due to its f/32 stop. The lens can be used for these applications without the leaf shutter. This lens was designed for flash work though and the ring on the front of the lens needs to be turned to engage the leaf shutter. I don't use mine for portraits but it has a good reputation for that work. </p> <p>A 35mm format portrait lens (90mm) at f/2.8 will have more DOF than a 6x7 portrait lens (180mm) at f/2.8. The 6x7 portrait lenses will separate your subject better than the 35mm portrait lenses. The 165mm f/2.8 for the Pentax has been used for portraits due to its wide open ability to separate subjects. The 200mm and 165 LS are only f/4. This camera was not designed primarily for portraits, so it does not have a lot of fast portrait lenses. The 105 is fast but is a bit short for most portraits. </p>

<p>It's OK for portraits but being an f/5.6 lens, will not give you the separation of subject that the 165 f/2.8 will. </p>

<p>Edward answered your question- no, you don't need tubes for portraits. I only use tubes on this lens for macro work. </p>

<p>"Is it okay to switch front and rear element groups from one lens chassis to <br />another? "<br> <br> And you want to do this because... ?</p>

<p>Nearly all lenses are corrected for spherical aberration at infinity and with the addition of a floating element (especially in wide lenses), allows them to perform well at close distances as well. In macro lenses, they are corrected for this aberration at close distances, so the use of a floating element there, assures infinity spherical correction. </p>

<p>Correction- My Honeywell body has a 403 SN, not 409. </p>

<p>I have a 415 serial numbered 6x7 that I bought new in 1988 and I have a Honeywell with no lock up with a 409 serial number. Given the time frame between these two models, I would estimate that your 413 camera was from 1986 to 1987. The lens is about the same time frame. </p>

<p>"I wonder if the focal length changes as you get closer to minimum focusing distance" Yes, the focal length does increase as you move to focus on closer objects. This is because the rays entering the lens are not parallel as when at infinity focus but diverging when entering the lens. Therefore the focal length has to be longer to accommodate this. That stationary element may be considered a floating element and if so, they are used to better correct spherical aberration in close focus situations. The two cross sections are highly modified Double Gauss designs that are pretty wild looking. </p>

<p>" I've never really seen a lens design like this before."<br> Nor have I. The 3 air spaced elements in front of the stop are pretty common in longer Double Gauss designs. The 6 elements behind the stop are what make it different from anything I've seen. This unique design does not fit into any category that I have seen. </p>

<p>Mark-- F/32 is not much of a problem. Yes there is some loss but if you need the DOF to make the shot, it is there to use. Using f/45 can be more of a problem and I rarely use it. </p>

<p>Keep in mind that if you intend to shoot landscapes with large DOF, f/22 is not going to serve you well (with the exception of the 45mm). Having a 55, 75 and 100mm focal length with f/32 makes a big difference (55-100 zoom). If you don't shoot in this style, then your primes will suite you well. </p>

<p>The DOF for this camera in landscape work will be a challenge compared with the Canon you have used before. In the late 1980's and early 1990's I had bought a number of the prime lenses for landscape and travel work. After struggling with DOF issues for years, I kept the 45mm, bought the 90-180 and 55-100 zooms for their small stops and never looked back. I also like the 165 LS (f/32) and its cousin, the 200 Pentax, also f/32. Both lenses use the same design type and are proven. I can't recommend the 300 Takumar, too much shutter shake softness. The 300 EDIF is a gem although it does not have the f/45 stop as the older version had. The 400 Takumar is an excellent lens, although not easy to use due to its outer bay mount. The rear filter bay cannot be used due to internal reflections that show up on film. A 105mm front filter can be used but have to be adapted to fit the lens hood with a spacer ring. The 400 EDIF is only slightly better but much more expensive. The 600 Takumar is a big and heavy beast but does well with the 1.4x converter, giving about the same magnification you got with the Canon and 400mm. The 600 is infamous for its CA in the f/4 to f/11 range, so it must be stopped down to avoid this. If you have the money, the 800EDIF is the way to go with high mag lenses. </p>

<p>Have you researched the Pentax 645Z before chasing the Hasselblad?</p>

<p>LUSENET- Now that brings back some memories. I was in the Pentax 6x7 part. </p>

<p>Thanks guys, I have sent the lens back to the seller for repair or exchange. </p>

<p>I've had this 28mm 3 cam, Elmarit-R lens for several months now but just now finished a roll of film. I'm using it on my Leicaflex SL2 body. Many of the slides have come back over exposed badly with infinity out of focus. I thought that the lens was not automatically stopping down to the set aperture when shooting but I checked the diaphragm on a test shot and it went from wide open to the selected stop. Could this be an intermittent auto diaphragm problem? Any ideas?</p>

<p>I have both the MLU version and the non-MLU type. The 200mm can be used with the non lock up body but the tripod and head must be heavy duty!</p>