[Bauie]

I have a K-x and have converted an old enlarger into a copy stand.

I am copying old maps and plans, some of which are approx 1 metre wide (3 feet). The lens I have been using is a DAL 1:3.5-5.6 18-55mm AL. I realise this is a cheap kit lens but for most applications, it is quite sharp at f8, however it doesn't perform very well for this copying work (soft edges regardless of aperture) I am thinking of splashing out on a Pentax Normal smc P-D FA 50mm f/2.8 Macro Autofocus Lens.
Pentax Normal smc P-D FA 50mm f/2.8 Macro Autofocus Lens 21530
I just wanted to run this past you guys, is this a good lens for what I will be doing? Also, what is the clamp thingie on this lens? Thanks for any help.

[Sandy Hancock]

The DFA 50/2.8 Macro would be perfect for the job if the focal length suits your subject distance. Otherwise the DA 35/2.8 Macro Limited might suit you better.

[Just1MoreDave]

The clamp thingie might be useful for your purpose, because you are always focusing at the same distance. You'd focus perfectly once, then switch off autofocus, clamp the lens at that point and the lens would never have to focus again.

That means you could also buy a manual focus macro lens (used). If your light levels change a lot, something like an SMC Pentax-A 50mm f2.8 Macro. That would allow the camera to set the aperture, more metering modes, works with an automatic flash better, just general better integration. If you have decent steady light or don't mind some extra work setting exposure, you can get something like an SMC Pentax-M 50mm f4 Macro pretty cheap - maybe $60-75.

[aslyfox]

this article might be of interest

Pentax currently offers three [ now four ] autofocus macro lenses: the DA 35mm F2.8 Limited Macro, D FA 50mm F2.8 Macro, and D FA 100mm F2.8 Macro [ D FA 100mm F2.8 Macro WR ]. Tamron also makes a 90mm F2.8 Macro. Note that the longer the focal length, the farther away you can be while maintaining life-size magnification.

Read more at: The Advantages of a Dedicated Macro Lens - Tutorial Videos | PentaxForums.com

both the D FA 50mm F2.8 Macro and the D FA 100mm F 2.8 Macro have the focus clamp which allows you to lock the manual focus position.

SMC Pentax-D FA 50mm F2.8 Macro Reviews - D FA Prime Lenses - Pentax Lens Reviews & Lens Database

SMC Pentax-D FA 100mm F2.8 Macro Reviews - D FA Prime Lenses - Pentax Lens Reviews & Lens Database

[dms]

Check the focal length you are using for the largest map, as a 50 mm lens may require you to be too far away from the map: above the peak height on your copy stand or simply so high that focusing and operating the camera is a pain. An older manual focus macro (max m=1/2) lens should be fine/actually likely preferable to a AF lens. The Pentax 50mm f/4 macro was mentioned and is quite good and inexpensive.

If you find that 50 mm is too long FL, some of the older 28mm or 35 mm lenses should do much better than a cheap zoom, or I would look for a better zoom but: (a) moderate aperture so it is not large and costly, (b) that does not cover a huge range of FL's. Zoom lenses can be very convenient in copying: they address the issue of huge vs small map being copied, and allow you to fine tune the crop w/o moving the camera and/or changing focus as you move the camera. Something like the Adaptall-2 35-70mm SP (model 01) or the Pentax FA 28-70mm f/4. Unfortunately I have not used any of these lenses for document copying so the actual distortion is not something I know, nor have I see test data. but I would think any of these would be much better than zoom you are using now. **

_____
** Actually the distortion numbers at 35mm and 55mm for your zoom are very low (I am surprised)--checking lenstip (for AL II version) and optical limits; however, edge sharpness is likely another story.

[Bertrand3000]

I would suggest the DFA 50 Macro 2.8. Not only it is sharp edge-to-edge, but the Clamp switch is actually very useful for Catch-in focus, something that the DA 35 Limited Macro does not have.

[ToddK]

I would determine what focal length covers your maps and plans best with your DAL 18-55 and then look at a macro closest to that FL. I would think 50mm is not wide enough. The 35mm macro may be easier to work with for what you are doing and is an extremely sharp lens.

[photoptimist]

As others have mentioned, 50mm will probably be too long. To copy a 1 meter wide subject on to APS-C sensor, the camera will need to be about 44 focal lengths from the map. With a 50mm lens, that's 2.2 meters. A 28mm lens might be a better idea -- it only needs about 1.2 meters of distance from camera to a 1 meter wide subject.

[Riddler]

35 mm macro Will do the job

[Bauie]

Thanks to all who have replied. I'm an old film guy so still think of a 50mm lens in terms of 35mm film angle of view. I messed around a bit last night and the 50mm (75mm equiv) would be too long, the 35mm (53mm equiv) would be much more useable. I guess the choice is between the HD Pentax-FA 35mm f/2 Lens
and the Pentax 35mm DA L f/2.4 AL Lens. Neither of these lenses are actually designated as macro, would one be better than the other for close work?

[BigMackCam]

Thanks to all who have replied. I'm an old film guy so still think of a 50mm lens in terms of 35mm film angle of view. I messed around a bit last night and the 50mm (75mm equiv) would be too long, the 35mm (53mm equiv) would be much more useable. I guess the choice is between the HD Pentax-FA 35mm f/2 Lens
and the Pentax 35mm DA L f/2.4 AL Lens. Neither of these lenses are actually designated as macro, would one be better than the other for close work?

Both have the same minimum focus distance of 30cm and more-or-less similar performance so far as your intended application is concerned. The FA35/2 (whether the older SMC or newer HD variant) has the advantage of being full frame compatible and having an aperture control ring, so you could use it on old Pentax K-mount film bodies or the K-1 digital, should you wish.

Alternatively, you might consider the DA35/2.8 Macro Limited. This is a proper macro lens with excellent performance. It has a minimum focus distance of 14cm and is designed for digital bodies with APS-C sensors.

[Bertrand3000]

Thanks to all who have replied. I'm an old film guy so still think of a 50mm lens in terms of 35mm film angle of view. I messed around a bit last night and the 50mm (75mm equiv) would be too long, the 35mm (53mm equiv) would be much more useable. I guess the choice is between the HD Pentax-FA 35mm f/2 Lens
and the Pentax 35mm DA L f/2.4 AL Lens. Neither of these lenses are actually designated as macro, would one be better than the other for close work?

Do not forget the DA 35 F2.8 Macro Limited. It's your best choice if 50mm is too narrow. Otherwise, I would recommend the much cheaper DA 35 F2.4 AL. It's one of the sharpest Pentax lenses outside dedicated macro lenses. I don't think the FA 35 is worthwhile for your usage, you don't need wide aperture, nor aperture ring, nor full frame compatibility.

Bottom line : if cost is not a problem, the DA 35 F2.8 Macro Limited is what you need for ultimate sharpness. Otherwise, the DA 35 F2.4 AL will do the job.

[K-Three]

For the size originals you have indicated, you really don't need a "Macro" lens (as you've found out using your 18-55). You do want something that is sharp from edge to edge, which true macros tend to be. They are flat-field lenses that are designed to keep focus across the subject at a constant distance.

What you need is a lens that allows close focus, and is sharp across the field. As photoptimist pointed out above, something in the 28 mm range might be the ticket for you.
The problem with most lenses shorter than 50mmm is that they are not flat-field. The 35 macro is, but I think it's still longer than you need. If you could find an old A, or M 24 or 28 mm lens, designed for full frame 35mm. On a crop body, you would be working only in the very center of the lens circle, and it should be sharp enough. Certainly better than the zoom you are using now. No need to get a fast one, an ƒ/3.5 or 4 would do fine.

For smaller objects in this set up, you may want to consider getting extension tubes. A thin extension tube on a short lens can get you close in a hurry.

Have you considered going to a copy shop and having these originals scanned? I work in an engineering office and we have a scanner built into our HP plotter, it does a pretty good job on linework drawings and maps. Can scan to either JPG or PDF, up to 36-in wide, and as long as you want. Just a thought

[bwgv001]

how does the "clamp thingy" look like. i have a DFA 100 WR macro, but there is nothing that i can identify as clamp thingy?

[Sandy Hancock]

how does the "clamp thingy" look like. i have a DFA 100 WR macro, but there is nothing that i can identify as clamp thingy?

The more recent WR version does not have a focus clamp. The non-WR DFA 100/2.8 macro does.