Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-26-2012, 08:36 AM   #1
Veteran Member




Join Date: Nov 2009
Location: Iowa
Photos: Albums
Posts: 2,269
Reverse stacking for macro onto a 100mm macro lens - 28mm good?

Hey all.

Wanting to try reverse stacking with my 100mm 1:1 macro prime mounted to the camera and another lens reversed on the end of that. So here's the question:

Would a 28mm reversed on the end of the 100mm be totally impossible to work with in the field? (3.57x magnification) or should I just stick with a 50mm at 2x magnification?

And what would the working distance be with a 28mm reversed?

Thanks,
Bob :-)

04-26-2012, 08:44 AM   #2
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
28mm you need a lot of light and you need to stop down your lens a lot to get a bit of sharpness or else the DOF is so thing.

So in the field i would go with the 50mm
04-26-2012, 09:12 AM   #3
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
I cover this technique a bit in https://www.pentaxforums.com/forums/pentax-lens-articles/152336-cheap-macro-b...lose-work.html

A 28:100 reverse-stack WOULD be unusable in most fields, unless you've setup a field lab. As Anvh said, you'll be working with very little light, and DOF is terribly thin. Your working distance would be the same as with any prime-reversal setup: about 45mm, the PK register distance. With the primary (100mm) at infinity focus, magnification is ~3.5:1; at close focus, somewhere upwards of there. You'll need light(s) and tripod and maybe a subject stage. Be sure to heed the other stacking rules: Leave the primary aperture wide-open; control the exposure by adjusting the aperture ring on the secondary (28mm); focus by changing camera+lens-to-subject distance, not the focus rings.

As with Anvh, I'd also recommend stacking nothing shorter than a 50mm onto your 100mm macro. Handheld fieldwork at 2:1 or greater is possible with a primary of 50mm or shorter, but hi.mag work is just pretty problematic with a 100mm primary.
04-26-2012, 09:28 AM   #4
Senior Moderator
Loyal Site Supporter
Nass's Avatar

Join Date: Aug 2009
Location: The British Isles
Photos: Gallery
Posts: 2,251
For this sort of magnification the best bet is the Canon system using an MPE-65 lens. This lens will take you up to 5:1. The reason that using this lens makes it possible is because the aperture stays wide open whilst you're composing and then stops down for the shot. No other system offers this.

I looked into having a widget buit that could do this for me on Pentax using a custom servo, but it's a bodge job and there probably wasn't enough (physical) space for it: this would be a battery controlled servo sitting in front of a reversed lens. Yuck. Ironically, this can be done with old fashioned SLR cameras using the Pentax dual remote used for slide copying; as the remote was pressed, one cord went to the reversed lens stopping it down for the shot and the other went to the camera, taking the shot.

I've played with 28 reversed onto over 100, it's tough.

04-26-2012, 10:59 AM   #5
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
QuoteOriginally posted by Nass Quote
The reason that using this lens makes it possible is because the aperture stays wide open whilst you're composing and then stops down for the shot. No other system offers this.
???? which system these day work with a close aperture, they are all wide open to let light through for the AF system.
04-26-2012, 01:36 PM   #6
Senior Moderator
Loyal Site Supporter
Nass's Avatar

Join Date: Aug 2009
Location: The British Isles
Photos: Gallery
Posts: 2,251
Right. But when you reverse your Pentax lens onto your other Pentax lens, you don't have the benefit of that, do you? Which was my point. If you reverse a Nikon lens onto a Nikon lens to get to 5:1 do you have the benefit of that? (aperture controlled from body on the reversed lens)
04-26-2012, 01:40 PM   #7
Senior Member




Join Date: Mar 2011
Posts: 119
QuoteOriginally posted by Nass Quote
Right. But when you reverse your Pentax lens onto your other Pentax lens, you don't have the benefit of that, do you? Which was my point. If you reverse a Nikon lens onto a Nikon lens to get to 5:1 do you have the benefit of that? (aperture controlled from body on the reversed lens)
Is the second lens (the furthest from the sensor) usually stopped down? I was under the impression it wasn't, and only the primary lens was stopped down.
04-26-2012, 01:50 PM   #8
Senior Moderator
Loyal Site Supporter
Nass's Avatar

Join Date: Aug 2009
Location: The British Isles
Photos: Gallery
Posts: 2,251
^^

Usually the reversed lens =)

*points up to Rio's note*

04-26-2012, 03:06 PM   #9
Veteran Member




Join Date: Nov 2009
Location: Iowa
Photos: Albums
Posts: 2,269
Original Poster
QuoteOriginally posted by RioRico Quote
A 28:100 reverse-stack WOULD be unusable in most fields, unless you've setup a field lab.
Righty-o. A 50 it is, then. :-)

Thanks,
Bobbo :-)
04-26-2012, 03:21 PM   #10
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
QuoteOriginally posted by alphanerd Quote
Is the second lens (the furthest from the sensor) usually stopped down? I was under the impression it wasn't, and only the primary lens was stopped down.
The primary (mounted on the camera) should be a prime (not a zoom) with its aperture wide-open, else you'll get moderate-to-terrible vignetting. The secondary (reversed) should have an aperture ring so you can control exposure. I just did a quick rough test (I'm hampered by having packed most of my lenses for my journey homeward) and it looks like the secondary can be a zoom. I reversed my F35-70 onto my Meyer Telemegor 240/4.5 and didn't see any vignetting.
04-27-2012, 02:56 AM   #11
Veteran Member
Anvh's Avatar

Join Date: Sep 2011
Posts: 4,616
QuoteOriginally posted by Nass Quote
Right. But when you reverse your Pentax lens onto your other Pentax lens, you don't have the benefit of that, do you? Which was my point. If you reverse a Nikon lens onto a Nikon lens to get to 5:1 do you have the benefit of that? (aperture controlled from body on the reversed lens)
Just use the aperture ring.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
100mm, 100mm macro lens, 28mm, k-mount, lens, macro, magnification, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
loved the idea of reverse-lens macro, BUT... slr_neophyte Troubleshooting and Beginner Help 18 08-31-2011 08:05 AM
Reverse lens macro Deni Pentax SLR Lens Discussion 12 06-15-2010 01:05 PM
Reverse lens? macro NicK10D Photographic Technique 4 06-10-2010 08:19 AM
Streets My first Macro lens, the DFA 100mm Macro WR. Here are my 1st few shots with it! aaronius Post Your Photos! 4 04-30-2010 07:23 PM



All times are GMT -7. The time now is 04:55 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top