Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
02-15-2019, 08:09 PM - 3 Likes   #16
Veteran Member




Join Date: Dec 2012
Location: Montr饌l QC
Photos: Gallery | Albums
Posts: 2,351
There's supposedly also a Laowa 100mm 2:1 upcoming, but it's taking a long time to materialize! I'm hoping it will at least have an aperture lever, contrary to the 60mm.

My goto setup for up to 2:1 magnification is a 100mm 1:1 macro plus a Raynox DCR-250. If you've not shot greater than lifesize before (which your phrasing kind of implies), I would recommend getting your feet wet with magnifications in the 1:1 to 2:1 range before attempting even higher, because the technical hurdles get more significant as the magnification increases. You should probably also be thinking not just about a lens combo, but also a flash & diffusion setup.

This, for example, is D-FA 100mm WR plus Raynox DCR-250 (on K-3):



02-15-2019, 08:40 PM - 1 Like   #17
Veteran Member




Join Date: Dec 2010
Location: Ontario
Photos: Gallery
Posts: 3,332
QuoteOriginally posted by Doundounba Quote
My goto setup for up to 2:1 magnification is a 100mm 1:1 macro plus a Raynox DCR-250.
I can second this combo (and the rest of your advice). That it can range from 1x to 2x lifesize and maintains an aperture lever make it very versatile, easily my go-to up to 2x mag. With cropping I'll often push it a little further before moving to my more awkward higher mag. setups..



02-15-2019, 09:21 PM   #18
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 28,161
You can add a macro add on lens like the raynox dcr-250 or 150. The extreme back site memtioned earlier can roughly indicate the final ratio.
02-16-2019, 07:34 AM - 2 Likes   #19
Senior Member




Join Date: Apr 2011
Location: Drome, France
Posts: 298
Micro is by definition between 10:1 and 100:1.
You will need very specialized stuff (e.g. microscope lens, micro slider, bellows, tube lens, etc.) and focus stacking will be your nightmare.

If you plan to shoot between 1:1 and 2:1, some good lenses are available: Laowa-Venus 60mm F/2.8 2:1 macro, Oshiro-Bresser 60mm F/2.8 2:1 macro.
If you plan to shoot between 2:1 and 10:1, you can try a short enlarger lens (e.g. Componon 28mm F/4) or a 5X or 10x microscope lens (if you can afford a MPlan APO ELWD episcopic one, it will be an excellent choice) but you will need some extra stuff (160mm or 200mm tube lens, specialized lighting).

I own lots of stuff but practically I mainly shoot handheld, between 1:4 and 2:1, most of time using a 90mm macro (sometimes with a DCR-250 close-up or with a 1.4x teleconverter), my new Irix 150mm macro or my Oshiro-Bresser 60mm macro, depending on the working distance I need.


Last edited by tryphon4; 02-16-2019 at 08:10 AM.
02-16-2019, 12:56 PM - 1 Like   #20
Pentaxian
jddwoods's Avatar

Join Date: Nov 2012
Location: Newark, Delaware
Posts: 1,035
QuoteOriginally posted by Adam Quote
The best solution IMO is to use close-up accessories, such as bellows, tubes, or reversal. There's only one 2:1 dedicated lens (from Venus I believe) and it's so-so.
Wouldn't the teleconverter also increase magnification to 1.4X? I use the TC with my DFA 100 WR macro and there appears to be a noticeable increase in magnification.
02-16-2019, 01:31 PM - 2 Likes   #21
Veteran Member




Join Date: Dec 2010
Location: Ontario
Photos: Gallery
Posts: 3,332
QuoteOriginally posted by jddwoods Quote
Wouldn't the teleconverter also increase magnification to 1.4X? I use the TC with my DFA 100 WR macro and there appears to be a noticeable increase in magnification.
Yup. I've used the tamron 1.4x TC with my dfa100mm with good results, and by all accounts the Pentax TC is better. This combo will give you 1.4x mag at the minimum focus distance. Alternatively, you can use the TC+DFA100 to get 1x mag but with a greater working distance than the DFA100 on its own.
02-16-2019, 03:33 PM - 1 Like   #22
Veteran Member




Join Date: Dec 2012
Location: Montr饌l QC
Photos: Gallery | Albums
Posts: 2,351
Yeah, if a 140mm WR prime would also pull double duty for tele shots (and you're shooting APS-C), then the HD DA 1.4X makes a lot of sense coupled with the D-FA 100mm WR. But it's much more expensive than a Raynox DCR-250, and personally, I find the greater working distance is actually a nuisance for my lighting setup. For most outings, I usually carry the K-3 with D-FA 100mm WR and Raynox DCR-250 pre-mounted and carry the HD DA 1.4X in the backpack. I'd rather shoot D-FA 100mm plus Raynox than D-FA 100mm plus the 1.4X tele-converter. I only reach for the 1.4X when I need even more magnification and then I shoot with all three - and it's a combination that works really, really well, IMHO.


Last edited by Doundounba; 02-16-2019 at 03:38 PM.
02-17-2019, 04:50 AM   #23
Senior Member




Join Date: Apr 2011
Location: Drome, France
Posts: 298
If I remember correctly, the initial goal was to get something 2x to 4x, so a 1.4x TC and a 1:1 100mm are not enough.

QuoteQuote:
Thanks for these comments. I actually have a Pentax 50mm macro lens for my K5. Photoptimist, would I therefor look for k mount tubes/bellows that are 100mm and 150mm long for the 2x and 3x?

Also what should one expect for depth of field. I imagine its rather small.



Either you keep your 50mm 1:1 and upgrades it (using bellows or extension tubes, you can also use a 1.4x TC additionally), or you need to change your macro lens.
However, it would not be a good idea to use a closeup lens with a 50mm (focal length will decrease and working distance so).

If your 50mm is a FA 50mm F/2.8, you can add a 65mm extension ring kit to get 2.3:1. If you add a 1.4x TC to this setup, you get 3.3:1, not so bad.
02-17-2019, 01:00 PM   #24
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 28,161
The existing 50mm macro plus a dcr250 and dcr150 stacked will give 2.28:1 magnification.

Also unlike extension tubes and bellows these will not reduce light.
02-17-2019, 01:29 PM   #25
Senior Member




Join Date: Apr 2011
Location: Drome, France
Posts: 298
UncleVanya, you are wrong, quantity of light that reaches the sensor is a matter of macro ratio, not a matter of register.


These two setups were used to perform some comparisons at 1:1. First, a Tamron 90mm macro F/2.8, then a Rodenstock Rodagon 135mm F/5.6 and some extension tubes and helicoid (21.75 cm).
Both lenses were used at F/8 and 100ISO, and for a same subject in the same light conditions, the shutter speed is respectively 1/15" and 1/13" to get about the same light level on the subject. The difference between 1/15" and 1/13" is not significant because the camera vs target alignments are handmade and not very precise.

In fact, I measured the speed shutter, at 1:1, F/8, 100ISO, under the same lighting and on the same subject (a post-it block with a rectangle which dimensions are the same that an aps-c sensor) on 7 setups:

Reference---------------Focal length (mm)-----Speed
Oshiro (Venus)------------------------60-----------1/10"
Rodenstock APO Rodagon---------50-----------1/10"
Tamron SP Di------------------------- 90-----------1/15"
Panagor PMC-------------------------90------------1/13"
Rodenstock Rodagon--------------105------------1/13"
Rodenstock Rodagon--------------135----------- 1/13"

The Rodenstock APO Rodagon 50mm setup uses a 5.75 cm extension length.
The Rodenstock Rodagon 105mm setup uses a 16.25 cm extension length.
The Rodenstock Rodagon 135mm setup uses a 21.75 cm extension length.

You can verify that, at 1:1, with several extension distances, the shutter speed is about the same.
The slight differences may be due to alignment differences and different optical formulas.


By the way, I own several close-up lenses (Nikon 5T, 6T, Sigma life size converter, Raynox DCR-250, LOMO AL-4) and if you are still sceptical I can include some close-up lenses in my test setup to complete the table.
Your error is very common, when I began macro I did the same.

Last edited by tryphon4; 02-17-2019 at 02:06 PM.
02-17-2019, 01:51 PM   #26
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 28,161
QuoteOriginally posted by tryphon4 Quote
UncleVanya, you are wrong, quantity of light that reaches the sensor is a matter of macro ratio, not a matter of register.


These two setups were used to perform some comparisons at 1:1. First, a Tamron 90mm macro F/2.8, then a Rodenstock Rodagon 135mm F/5.6 and some extension tubes and helicoid (21.75 cm).
Both lenses were used at F/8 and 100ISO, and for a same subject in the same light conditions, the shutter speed is respectively 1/15" and 1/13" to get about the same light level on the subject. The difference between 1/15" and 1/13" is not significant because the camera vs target alignments are handmade and not very precise.

In fact, I measured the speed shutter, at 1:1, F/8, 100ISO, under the same lighting and on the same subject (a post-it block with a rectangle which dimensions are the same that an aps-c sensor) on 7 setups:

Reference Focal length (mm) Speed
Oshiro (Venus) 60 1/10"
Rodenstock APO Rodagon 50 1/10"
Tamron SP Di 90 1/15"
Panagor PMC 90 1/13"
Rodenstock Rodagon 105 1/13"
Rodenstock Rodagon 135 1/13"

The Rodenstock APO Rodagon 50mm setup uses a 5.75 cm extension (helicoid)
The Rodenstock Rodagon 105mm setup uses a 16.25 cm extension (tubes and helicoid)

You can verify that, at 1:1, with several extension distances, the shutter speed is about the same.
The slight differences may be due to alignment differences and different optical formulas.

Reading on this it does appear you are right however there are odd caveats in what I read.
02-18-2019, 08:59 AM - 1 Like   #27
Veteran Member




Join Date: Dec 2010
Location: Ontario
Photos: Gallery
Posts: 3,332
QuoteOriginally posted by UncleVanya Quote
The existing 50mm macro plus a dcr250 and dcr150 stacked will give 2.28:1 magnification.

Also unlike extension tubes and bellows these will not reduce light.
Sort of, but there's no free lunch. Tubes increase the effective f-stop. This reduces light but also gives you a hand by a corresponding increase to the DoF. If you want the same DoF with the closeup filter (which don't increase the effective f-stop), you have to stop the lens down by a comparable amount and the net result ends in a wash*. For more details on the applicable terms & conditions, see: Macro Extension Tubes & Close-up Lenses and also Macro Camera Lenses.

An achromatic close up filter will still be my choice over tubes, at least partly because I don't have tubes with aperture coupling and the filters are much easier to work with.


* note it's a a win for the closeup filter setup if you want a narrower DoF. But as magnification increases, this isn't usually considered a plus. However, more flexibility on the wide end does help avoid diffraction but stacking really gets mandatory.
02-18-2019, 11:18 AM   #28
Senior Member




Join Date: Apr 2011
Location: Drome, France
Posts: 298
QuoteOriginally posted by BrianR Quote
Tubes increase the effective f-stop. This reduces light but also gives you a hand by a corresponding increase to the DoF.
No! Did someone reinvent optic and physic laws?

QuoteOriginally posted by BrianR Quote
An achromatic close up filter will still be my choice over tubes, at least partly because I don't have tubes with aperture coupling and the filters are much easier to work with.
A closeup is a good idea with a long focal lens, definitely not with a 50mm as tou may lose all your working distance.


BrianR, did you read my previous post?
02-18-2019, 11:39 AM - 2 Likes   #29
Veteran Member




Join Date: Dec 2010
Location: Ontario
Photos: Gallery
Posts: 3,332
QuoteOriginally posted by tryphon4 Quote
No! Did someone reinvent optic and physic laws?
Are you saying extension tubes don't increase the effective f-stop? Please be specific. Refer to the links I provided and point out what parts you disagree with.

QuoteOriginally posted by tryphon4 Quote
BrianR, did you read my previous post?
The one responding to UncleVanya's comment about closeup filters? Where you gave examples using only extension tubes and not closeup filters?

My own tests show (at the same light source, iso & shutter speed):

DFA100mm focused @ infinity on 100mm of tubes to give 1:1 magnification is little over 1.5 stops underexposed compared to the same DFA100mm+Raynox DCR250 with the dfa focused to about 70cm (this gives 1:1 mag when coupled with the raynox).

Same magnification, same f/stop on the lens, the extension tube version is much darker than with the closeup filter. DoF is correspondingly less with the close up filter.
02-18-2019, 11:55 AM - 2 Likes   #30
Pentaxian
photoptimist's Avatar

Join Date: Jul 2016
Photos: Albums
Posts: 5,113
QuoteOriginally posted by tryphon4 Quote
No! Did someone reinvent optic and physic laws?

A closeup is a good idea with a long focal lens, definitely not with a 50mm as tou may lose all your working distance.


BrianR, did you read my previous post?
Actually, BrianR is right and it is the laws of optics and physics that creates the differences between tubes and close up lenses.

Tubes: The extension of the lens with a helicoid or tubes to get to 1:1 doubles the distance from the lens to the image plane, causing a 1/r^2 light loss of two stops, and a narrowing of the effective focal length by two stops.

Close-up Lenses: This combination creates a merged lens with an overall shorter focal length but approximately the same physical aperture which implies a wider numerical aperture. This combination still has extension in it to get to 1:1 but it starts with a larger effective numerical aperture.
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, 150mm, 2x, depth, field, k-mount, lens, macro, macro than macro, pentax, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
HSS with non A Setting K Mount Lenses (ie capped at 1/200) BruceBanner Flashes, Lighting, and Studio 21 11-30-2018 02:43 PM
Wide angle Lens for K-1 (ie FF) that takes 52mm ND Filters BruceBanner Pentax SLR Lens Discussion 30 08-16-2017 12:53 PM
Colors IE vs Firefox? TenZ.NL Digital Processing, Software, and Printing 5 01-01-2014 12:55 PM
Do ancient documents (ie: different nations' Constitutions) have relevance today? lesmore49 General Talk 15 07-10-2010 12:54 PM
Tokina (ie, Pentax) 50~135mm /f2.8 lens review at Watch Impress Katsura Pentax SLR Lens Discussion 7 12-19-2006 06:38 PM



All times are GMT -7. The time now is 04:02 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