Just touching bases. All have rocketed me into abilities I would not have imagined. Thanks all. Shooting silver dollars with a Pentax K-x with a Sigma 50mm lens. Results are good, but I need to look at the next horizon. Yes, I know the Rodenstock 75mm APO slide duplicator is the world's best. But I may not be ready for the world's best. Considering an in-between step. So what are the advantages/disadvantages of a Pentax bellows system (available on ebay for $59) or a Pentax tube extender system (available on ebay for about $15.) Won't purchase anything unless I get enough feedback. Thanks everyone, And have a Happy Thanksgiving, Kurt
The advantage of the bellows is you can adjust the magnification in fine increments. Let's say you want to exactly fill the viewfinder with a Dollar. You can do that with the bellows. This assumes the lens is long enough and/or the bellows has short enough minimum distance to get the magnification you need.
Tube extensions do the same thing as the bellows except they can't be adjusted in fine increments. You need to accept the magnifications the different combinations give you. If the combinations give you what you want, all's good. But this is a big disadvantage if you want to shoot a Dollar and the magnification is just a little too high and makes the Dollar over-fill the finder, while the next adjustment down only half-fills the finder. You can mitigate this by buying a longer lens, which will give you finer adjustment for the same tube lengths. But you may need to buy two sets of extenders to get enough extension for smaller coins or varieties.
Fixed magnification is actually an advantage in the sense that it is easy to precisely go back to a fixed magnification setting. Your Dollars will all be the same size for every shot. This can save a lot of time, but only works if you can find that just-right length of extensions you are satisfied with.
One more comparison: bellows have integrated tripod mounts, but most extension tubes do not. This means you will need to mount the camera rather than bellows to the tripod or copy stand. So if you use the camera dedicated for coin photos, no problem. But if you are like me, and use the camera for other purposes, swapping back and forth becomes tedious and requires re-calibrating flatness and other parameters each time I want to take a shot. The fixed bellows setup is easy to swap the camera on and off and maintains its settings.
The risk you take with bellows is that your magnification will be too high because your lens is too short or bellows minimum length is too long. If you were mostly imaging Cents, this is no problem. But I've had issues with some bellows not being able to image Dollars with shorter lenses. From my experience, 75mm is about the shortest you can go with most bellows and still image Dollars. I have one bellows that won't work for Dollars with anything shorter than 80mm. So if you go the bellows route, and don't want to take the risk, 105mm is a safer bet. The longer lens will also give you more working distance and thus lighting flexibility.
My recommendation would be the bellows, plus a 105mm EL-Nikkor. You'll need a PK-M39 adapter.
Hope this helps...Ray
PS forgot to mention: don't even think about putting your 50mm lens on bellows and imaging Dollars. It's not going to happen. Too much magnification.
Ray, Thanks. As a newbie working from a recipe or two to take Morgan shots, I get easily confused by the technicalities. Your response leaves my brain about as jumbled as my pet turtle's when he found his way into the spin dryer. Except for your PS. That message is as clear and serious as when Mom told me not to put a screwdriver into the wall socket. The difference is that this time, I'll listen . No single element of photography is beyond my comprehension, but trying to do it all at once and expecting the same results as seasoned veterans is not realistic. I think that I should take a photography class at the local tech school, and build on a solid foundation. But until then, I'll continue to use suggested formulas. I'll re-read your much appreciated advice a few times, and then start my research. I still have about a thousand other questions, but we'll save them for another time.
Kurt...The camera still works the same as it normally does, and the shutter is in the camera. The combination of adapters, bellows, and lens acts the same as if it were just a lens attaching to the camera.
What lens did you get? And as I remember you have a Pentax with P-K mount, correct?
Oh, Thank God... The shutter is in the camera... When I couldn't find it in the lens, I thought I just bought an expensive ant burner.
The lens is the Nikon EL-NIKKOR 1:5.6 f=105mm SN 3332544 earlier type with stainless mounting ring.
You're orrect on the camera. K-x (and to my embarassment,) in bright red. Dark duct tape may be in order. In my excitement, I ordered a PK-M42 adapter I'll take a few deep breaths and order the M39 thread to PK adaptor. Then I need to look at the bellows. The assemblage is another question. I could hang it all from a 1/4" screw on my shooting stand, or construct a copy stand where the camera is horizontal. I have two priorities. Select a good bellows system. And evict my Mother-In-Law so that I can dedicate her bedroom to a camera room.
If you can help with bellows recommendations, I can deal with the Mother-In-Law. I'll get some of this right. And take a beating for the parts I don't. Thanks for your help. Kurt
The 1/4 inch should mate with the bellows just fine...I use a tripod in the same fashion..using it to get the distance for the shot depending on the coin and the magnification I desire...I do not.. while the tripod is a workable deal, the camera stand weather bought or built. is the better option.. its fixed and sturdy, its the lenses that require the overall distances "TO" focus lengths....pennies don't require a 105MM lens, yet 75MM just wont get a Morgan into the right perspective..80MM might get it, 100/105 has no difficulties, 135mm is a lens one can easily find cheap... As Ray has superbly noted, the bellows allows allows the user to have a greater fine tuning on the picture.. It also allows the user to have the lens very close to the camera(less magnification) and the ability to extend the lens farther away from the camera(greater magnification).. While one will in the beginning seem to only get this darn lens into focus...is due to the fact that each situation has its own focal distance....some are at say 6 to 8 inches, and others at 14 to 24 inches from the subject.. This is one of the main learning curves using the bellow...not only for the coin size which is very important Verses the lens size, say half dollar and below 75MM for full coin shots, and 80MM , my idea is 100/105MM for full size dollar shots...... Now back to the focal/ bellows lengths....with your coin/what ever..and the bellows not extended...you can get a nice clean shot of the whole coin.....by extending the bellows to almost its extreme length..you can receive great Macro shots... The trick is........to set the bellows lens length first...depending if you want macro or full shots... near collapsed bellows for full size..fully extended for macro.. Then move the camera/tripod up or down to find the focal plane..(where it comes into focus.)...now the bellows adjustments really shine!slight adjustments result in crisp clean and clear pictures.... all you have to do now is get the lighting correct LOL....
Kurt...Glad I don't have to deal with the Mother-In-Law. Macro lenses, bellows, lighting are all MUCH simpler and more pleasant!
The lens you got sounds excellent, good choice. One thing you will want to do is open up aperture wide open and shine a penlight or a Jansjo light through it to see how clear the inner elements are. If they are clean and clear, you're AOK. If not, write back and I'll describe the cleaning procedure for this lens.
The bellows choice is fairly critical since it's one of the more expensive elements of the setup and it is also the "core" since it will stay in place while you change lenses, take your camera on and off, etc. The mounts chosen also define what adapters you are going to need. So at this point you have:
Camera with PK mount PK-M42 adapter M39 lens
Personally, I prefer the bellows to have a "universal" or "intermediate" mount type such as M42 or T-Mount. Then you can use just one adapter on either side of the bellows to go from camera to bellows and from bellows to lens. The other option is to go with a bellows that the camera mounts to, and then get an adapter for the lens side. I don't recommend trying to buy a bellows to match the lens, since while M39 bellows are out there, they are hard to find adapters for to mount the camera. Much easier the other way around.
For option 1, you only have a couple bellows available for PK mount both sides. This limits you to either a low end or high end bellows, nothing in the middle ranges. On the low end ($40) you will need to add extra bracing to keep the system stable. It will work but will take more work to get sharp shots. Here is an example on eBay:
This option looks more complicated but would be my recommendation. You may also need some extension between the PK/M42 adapter (this is the adapter you already bought, right?) and the bellows to allow rotation and choice of orientation. If you need this extra extension, you'll be glad you have a 105mm lens! For the M42/M39 adapter I recommend one of the "helicoil" type adapters that simply thread onto an M39 lens and make it "look" like an M42 lens.
For the bellows, this particular Pentax Auto Bellows is a bit too expensive but if you can find one for less than $100 this is the model I would recommend. They are high precision instruments, in my opinion better than the Nikon PB6 and on par with the Canon Auto Bellows yet in a flexible M42 mount:
An excellent alternative would be one of the Vivitar bellows. They have several series, and even offer an M42 bellows (Called Triple Track) that is excellent but none available on eBay right now. Most Vivitar bellows will be T-Mount, and you will need to adapt on both sides. Here is an example:
I am not sure how available the T/M39 Adapter will be. The lower option allows you to use PK lenses, M42 lenses, or M39 lenses so might be a good choice. Here is an example of this bellows going for a decent price:
FL = Focal Length of lens M = Magnification RD = Register Distance BE = Bellows Extension
FYI, the Register Distance is the distance from the sensor to the surface of the lens mount register. For example, my Nikon camera has a bayonet mount with register distance of 46.5mm. So if I mount a lens to the camera, it automatically starts at 46.5mm extension from the sensor. Some other common register distances are:
Let's further define the total extension TE which includes bellows extension plus register distance:
TE = RD + BE
Then we can write a simple equation for magnification as:
M = TE/FL - 1
Rearranging this for TE gives:
TE = FL(M+1)
Let's put some numbers to it. My Nikon DX-format camera has a ~16mm tall sensor. A Morgan dollar is 38mm in diameter, exactly twice the diameter of the Lincoln Cent. So for a Morgan dollar to fill the frame, magnification needs to be 16/38 = 0.42 and for the Lincoln Cent magnification is 16/19 = 0.84.
So for a 50mm lens, for a Morgan dollar and Lincoln Cents the Total Extensions need to be:
TE = 50(0.42+1) = 71mm for Morgan dollar TE = 50(0.84+1) = 92mm for Lincoln Cent
Using my Nikon as an example, we can figure out the bellows extension required for these coins. Since the Nikon register distance is 46.5mm, and the bellows extension BE = TE - RD, the bellows extensions are:
71 - 46.5 = 24.5mm for Morgan dollar 92 - 46.5 = 45.5mm for Lincoln Cent
This illustrates the problem. You are only allowed a bellows extension of 24.5mm to get a full field view of a Morgan dollar with a 50mm lens. More extension means higher magnification. I don't know of a bellows out there that can shrink down as small as 24.5mm. Most start at ~45mm minimum. Assuming 45mm minimum bellows extension, the minimum focal length needed for imaging a Morgan dollar is 64mm. I have had good results with a wide range of bellows using 75mm lenses, but some bellows (especially if adapters are required) may need 80mm minimum. To be safe, assuming some adapters and desire to go a bit bigger than a Morgan dollar, I usually recommend 105mm lenses for bellows work.
I see. You guys are operating like a wrestling tag team. I can't keep up. No one concept is beyond my comprehension. but all together, it is a bit much. Especially without time to digest. I have some personal commitments that take up all my free time. And this whole concept of having to work for a living vs. born beautiful, winning the lottery, or inheritance isn't working well for me. My days in the salt mine leave me with less free time than I would like.
So, the best I can do for this evening, is thank you all for a technical response that would rival that of any CIA Intelligence team. Hope that you didn't bake it from scratch just for me, but could cut and paste from your earlier works.
Be patient, I'll get stuff. And work with it. And post pictures. And suffer the humiliation of common mistakes. Go into therapy. And one day produce good images. And I've promised Kitten to get rid of the Poison Plant colection in order to fund my photography needs.
Thanks all, and I'll keep you posted on my progress. Kurt
PS We found a nice 6' x 8' trailer for 'Mom' that reminds her of her former residence. Things are looking up. Have a Happy New Year
Kurt...nope, wrote that all from scratch just for this thread. But don't feel bad, I have to work for a living just like most of the folks here, it's just that I have this week off since my work is having a power shutdown to service some equipment and they closed the plant. In all my years at the company, they have threatened to do this almost every year, but this is the first year they actually went through with it. Bless them! The wife and I went for a road trip Mon/Tue/Wed to Long Beach, where I picked up some 57D and 58D BU Cent rolls to search, and had some great walks on the beach and such. Most of my photo gear is packed waiting for our imminent move-in, which keeps pushing out as we discover more and more to be done. Today I had to supervise some workers, but tomorrow, Sat and Sun they are working on their own doing some flooring tile removal that I don't want to be anywhere near so it's 3 days of doing nothing. So again, don't feel bad, I'm just lucky to have enough time to write a bit.
Therefore, since the stock lens on my Olympus is a 14-42 mm zoom, then I could possibly get away with a tube setup, instead of a bellows. Because I'd still have the zoom capability to adjust magnification?