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12-27-2017, 07:14 AM   #1
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SMC Pentax-FA 100mm F2.8 Macro

I have bought on Ebay a wonderful SMC Pentax-D FA 50mm F2.8 Macro. The only problem is the short distance from subject at 1:1 ratio to light well with the flash. In the past I used a 135/3.5 with tubes and the distance was enough. I thinked to solve my problem with the 100/2.8, but the external lens is 5cm inside of lens body therefore subject is at the same distance of 50/2.8. do you know if the D FA 100/2.8 do not have the same problem of FA 100/2.8?

thanks

claudio

12-27-2017, 07:42 AM   #2
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Measured from the front of the filter ring to the subject when at minimum focusing distance, the dfa100mm/2.8 (non-WR model) has a working distance of approximately 13cm. The front lens element is recessed a little under 2cm from the front filter threads. AFAIK the WR-model has nearly the same physical dimensions (up to different coatings and aperture blades, the optics are the same).
12-27-2017, 08:26 AM   #3
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The FA 100 macro front element is very recessed, the DFA 100 has a slightly less recessed element. However another idea is to put a 1.4x converter on. This allows a larger magnification, which means you can increase the distance to the subject and get the same framing/detail.
12-27-2017, 08:40 AM   #4
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selections from the " In Depth Review " of the D FA 100mm 2.8 WR

The lens covers the full 24x36mm format, not just APS-C. The aperture blades are rounded, delivering a smoother bokeh which is important for a macro lens. However, unlike its predecessor, it has no aperture ring

The optical design is the tried-and-proven formula of the previous generation D FA 100mm F2.8 Macro lens, which in turn had inherited the optical design from the well-respected FA 100mm F2.8 and F 100mm F2.8 macro lenses introduced in 1991 and 1987, respectively. None of these earlier lenses had rounded aperture blades. . .

Macro Capabilities
This is a true macro lens with a flat field of focus and which focuses all the way down to life-size (1:1) magnification. Next to the distance scale it has a scale showing the magnification. Close-up lenses which screw into the filter ring are the best option for achieving magnification beyond 1:1, since bellows and extension tubes cannot be used: there is no way to set the aperture with bellows and extension tubes since the lens has no aperture ring.


Pentax-D FA 100mm F2.8 WR Macro Review - Introduction | PentaxForums.com Reviews

I like my D FA 100mm F2.8 ( non WR ) it is very good even when not used as a macro lens

however I don't use a flash with mine

12-27-2017, 04:31 PM   #5
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QuoteOriginally posted by UncleVanya Quote
The FA 100 macro front element is very recessed, the DFA 100 has a slightly less recessed element. However another idea is to put a 1.4x converter on. This allows a larger magnification, which means you can increase the distance to the subject and get the same framing/detail.
UncleVanya the problem is the very recessed front element. I measured it tonigt: it's 35mm from front element to filter flange. Add 150mm of lens body at 1:1 and the distance from sensor to the mount flange on the camera body of 45.46 mm you have 195,46mm that subtracted from 306mm (minimal focus distance at 1:1) leave just 111,54mm from filter flange to subject distance. This is just a little more (66mm) than 1:1 focus distance (45,54mm) on D FA. 50/2,8. My doubt is if it's worth while to change the fa 100/2,8 macro with a D FA 100/2,8 to recover these 35mm considering that optically these lens are identical. Your idea to put a 1.4x converter solve the distance problem but demage the wonderful optic quality of the lens. Sorry for my bad english.
Claudio
12-28-2017, 07:34 AM   #6
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QuoteOriginally posted by babbo natale Quote
UncleVanya the problem is the very recessed front element. I measured it tonigt: it's 35mm from front element to filter flange. Add 150mm of lens body at 1:1 and the distance from sensor to the mount flange on the camera body of 45.46 mm you have 195,46mm that subtracted from 306mm (minimal focus distance at 1:1) leave just 111,54mm from filter flange to subject distance. This is just a little more (66mm) than 1:1 focus distance (45,54mm) on D FA. 50/2,8. My doubt is if it's worth while to change the fa 100/2,8 macro with a D FA 100/2,8 to recover these 35mm considering that optically these lens are identical. Your idea to put a 1.4x converter solve the distance problem but demage the wonderful optic quality of the lens. Sorry for my bad english.
Claudio
The HD DA 1.4x doesn't seem to degrade shots I've made with my DFA 100.

Another option is a ringlight.
12-28-2017, 08:35 AM   #7
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QuoteOriginally posted by Aslyfox Quote
there is no way to set the aperture with bellows and extension tubes since the lens has no aperture ring.
Which i don't believe since there are even macro extenders with electronic AF contacts for KAF.
Mentioned also here in the forum.
12-28-2017, 08:38 AM   #8
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QuoteOriginally posted by angerdan Quote
Which i don't believe since there are even macro extenders with electronic AF contacts for KAF.
Mentioned also here in the forum.
you could be right

I have no personal experience with using bellows or extension tubes and I don't own the lens

I thought I made it clear that I was just directly quoting what was in the " In Depth Review " of the D FA 100mm F2.8 Macro WR:

" Pentax-D FA 100mm F2.8 WR Macro Review

Macro Capabilities

This is a true macro lens with a flat field of focus and which focuses all the way down to life-size (1:1) magnification. Next to the distance scale it has a scale showing the magnification. Close-up lenses which screw into the filter ring are the best option for achieving magnification beyond 1:1, since bellows and extension tubes cannot be used: there is no way to set the aperture with bellows and extension tubes since the lens has no aperture ring. "


Read more at: https://www.pentaxforums.com/reviews/pentax-d-fa-100mm-f28-wr-macro/macro-ca...#ixzz52ZRPIJx8

---------- Post added 12-28-17 at 09:43 ----------

QuoteOriginally posted by UncleVanya Quote
. . . Another option is a ringlight.
Pentax does have one

PENTAX AF 160FC Auto Macro Ring Flash reviews - Pentax Camera Accessory Review Database

if $$ is an issue ( when isn't it ) perhaps you can find an " experienced " one


Last edited by aslyfox; 12-28-2017 at 08:45 AM.
12-28-2017, 11:19 AM   #9
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QuoteOriginally posted by babbo natale Quote
UncleVanya the problem is the very recessed front element. I measured it tonigt: it's 35mm from front element to filter flange. Add 150mm of lens body at 1:1 and the distance from sensor to the mount flange on the camera body of 45.46 mm you have 195,46mm that subtracted from 306mm (minimal focus distance at 1:1) leave just 111,54mm from filter flange to subject distance. This is just a little more (66mm) than 1:1 focus distance (45,54mm) on D FA. 50/2,8. My doubt is if it's worth while to change the fa 100/2,8 macro with a D FA 100/2,8 to recover these 35mm considering that optically these lens are identical. Your idea to put a 1.4x converter solve the distance problem but demage the wonderful optic quality of the lens. Sorry for my bad english.
Claudio
I will reiterate:

I have the DFA100mm non-WR model, which has identical optics to the DFA100mm WR, and looks to have identical length measurements and the same recessed front element.

The working distance of my DFA100mm non-WR is approximately 13 cm at 1:1 magnification. This is the distance from the subject to the front filter threads.

It looks like you'd get about 2cm worth of extra working distance compared to your FA100mm. 11cm to 13cm hardly seems worth it to me to go through a gear swap, but it's your call. The newer models are also overall much lighter and more compact. The WR model loses the aperture ring as mentioned above, but the DFA100mm non-WR still has one if it's important to you.

I'd also second the teleconvertor as an option to try. I've been happy using the Tamron 1.4x behind mine, many other users have shown great results with the latest Pentax 1.4x and their dfa100mm macros.
12-28-2017, 04:47 PM   #10
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The DFA models are of a different body and optical design than the older FA, which is a fine macro lens, so the size is bound to be different but the newer models are reported to have better contrast characteristics, especially at larger apertures, and of course the WR model has that desirable feature. I do love shooting macro subjects in drippy conditions. It is also a better-built, more svelte design, but without the aperture ring.
12-28-2017, 06:09 PM   #11
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QuoteOriginally posted by mikesbike Quote
The DFA models are of a different . . . optical design than the older FA, . . . .
I am sorry perhaps I misunderstand but as I quoted from the "In Depth Review " in #4 and BrianR says in #9,

the optical design of the lenses are the same in both of the D FA lenses as well as the FA and F lenses

details of each lens can be found by looking at the review of the lens by going up to " Lenses " and looking under D FA primes, FA primes and F prime

Last edited by aslyfox; 12-28-2017 at 06:20 PM.
12-29-2017, 09:45 AM   #12
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QuoteOriginally posted by babbo natale Quote
I have bought on Ebay a wonderful SMC Pentax-D FA 50mm F2.8 Macro. The only problem is the short distance from subject at 1:1 ratio to light well with the flash. In the past I used a 135/3.5 with tubes and the distance was enough. I thinked to solve my problem with the 100/2.8, but the external lens is 5cm inside of lens body therefore subject is at the same distance of 50/2.8. do you know if the D FA 100/2.8 do not have the same problem of FA 100/2.8?

thanks

claudio
As I understand things, your problem is lighting at 1.1. You might try a ring light which can be had for well under $50. I have the DFA 100 macro and a Neewer ring light which I use successfully. From the front glass to the end of the ring light when mounted is no more than 6cm. Given a 13cm working distance (as one poster has noted), I think this leaves plenty of room to get done what you want. I can verify all this later and post my results if you would like.
12-30-2017, 05:22 AM   #13
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QuoteOriginally posted by Aslyfox Quote
I am sorry perhaps I misunderstand but as I quoted from the "In Depth Review " in #4 and BrianR says in #9,

the optical design of the lenses are the same in both of the D FA lenses as well as the FA and F lenses

details of each lens can be found by looking at the review of the lens by going up to " Lenses " and looking under D FA primes, FA primes and F prime
I know that optic design is the same. I ask if on DFA 100 front element is recessed like in FA100 stealing precious cm to the subject.
TNKs

claudio

---------- Post added 12-30-17 at 05:29 AM ----------

QuoteOriginally posted by BrianR Quote
I will reiterate:

I have the DFA100mm non-WR model, which has identical optics to the DFA100mm WR, and looks to have identical length measurements and the same recessed front element.

The working distance of my DFA100mm non-WR is approximately 13 cm at 1:1 magnification. This is the distance from the subject to the front filter threads.

It looks like you'd get about 2cm worth of extra working distance compared to your FA100mm. 11cm to 13cm hardly seems worth it to me to go through a gear swap, but it's your call. The newer models are also overall much lighter and more compact. The WR model loses the aperture ring as mentioned above, but the DFA100mm non-WR still has one if it's important to you.

I'd also second the teleconvertor as an option to try. I've been happy using the Tamron 1.4x behind mine, many other users have shown great results with the latest Pentax 1.4x and their dfa100mm macros.
I think that 2cm do not worth while change the lens. I will try with ring flash and 1.4x PENTAX.

TNKs

claudio

---------- Post added 12-30-17 at 05:38 AM ----------

QuoteOriginally posted by BrianR Quote
I will reiterate:

I have the DFA100mm non-WR model, which has identical optics to the DFA100mm WR, and looks to have identical length measurements and the same recessed front element.

The working distance of my DFA100mm non-WR is approximately 13 cm at 1:1 magnification. This is the distance from the subject to the front filter threads.

It looks like you'd get about 2cm worth of extra working distance compared to your FA100mm. 11cm to 13cm hardly seems worth it to me to go through a gear swap, but it's your call. The newer models are also overall much lighter and more compact. The WR model loses the aperture ring as mentioned above, but the DFA100mm non-WR still has one if it's important to you.

I'd also second the teleconvertor as an option to try. I've been happy using the Tamron 1.4x behind mine, many other users have shown great results with the latest Pentax 1.4x and their dfa100mm macros.
sorry I answer to another post the answer to your post. here it is.
I think that 2cm do not worth while change the lens. I will try with ring flash and 1.4x PENTAX.

TNKs

claudio
12-30-2017, 07:05 AM   #14
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Claudio, the element isn't recessed very much but as you have been given more specific info here's a picture:

http://www.kenrockwell.com/pentax/images/100mm-f28-wr/D3S_2632-1200.jpg
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