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06-28-2019, 10:20 AM   #1
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First macro lens : Sigma 70mm or Pentax 100mm ?

Hello everyone,

I am looking to acquire my first macro prime lens, as macro photography has been attracting me more and more these past years. I currently have the possibility to purchase either the Sigma 70mm f/2.8 EX DG or the Pentax D-FA 100mm WR for the same price.

My current setup is the 15mm Limited for landscape and the Pentax F 28mm as a walkaround lens. I also have the Pentax M 50mm: it was the first lens I bought apart from the kit lens but since I got the 28mm, I find the 50mm either too long, or too short as a telephoto. Last holidays I took, it only served for 1% of the shots over 700 so I'm thinking of getting rid of it...

Concerning the macro lenses, I was originally more attracted to the Pentax 100mm, but the Sigma 70mm seems to better complete my setup if I also want to use it for candid portraiture outdoors, for architectural details or telephoto landscape. I'm afraid the Pentax 100mm would be too long for those purposes and that the gap between my 28mm and the 100mm would be too important.
On the other hand, the Sigma 70mm seems huge and heavy in comparison with the 100mm, and I fear it would be too short for the macro use I'd like to give it (which is the primary goal of that acquisition!).

Thus my questions:
- Could the Pentax D-FA 100mm WR be easily used for other purposes than macro? I found in other posts various examples of portraits and telephoto landscapes taken with this lens but wouldn't the gap between my 28mm and the 100mm be frustrating?
- Is the Sigma 70mm f/2.8 EX DG long enough for macro photography of bugs? Not necessarily dragonflies or that kind of flying little things that I know are easily afraid, but mostly the crawling bugs that wander around the vegetables in my garden And are the weigh and size of the lens a real bother as a telephoto lens ? I don't mind those criterias as a macro lens, but if I had to carry the lens through an entire trip as a telephoto, it would definitely hold me back.
- And one last completely subjective question, if given the choice between the two of the them, which of those lenses would you have?

Thanks a lot !

06-28-2019, 10:39 AM   #2
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I think the Sigma is a full frame lens I thought it was no longer made in K mount. The advantage to the 70 sigma would be that if you get a K1 at some time it would be useful on it also
06-28-2019, 10:40 AM - 1 Like   #3
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Macros are great all-purpose lenses, usually with better edge to edge sharpness than non-macro lenses, but slower focusing because of the longer focus range. Most macros go to1:1, so think of the size of the sensor and the size of your subject. If you place your subject on the sensor how much would it cover. So of the shelf not all that useful for really small things. But a 1.4 TC can bump it up a bit and extension tubes etc are also possible.

In a recent poll I used the Sigma 70 on my K-3 and the DFA 100 macro on my K-1.
Full frame or APS-c, you be the judge. -

My choice would be the Sigma 70 as a studio lens and the DFA 100 macro as a walk around and capture images in the great outdoors lens. WR does make a difference from time to time. But in terms of IQ, they are pretty similar.
Just to add more contradictory stuff, I only bought the Sigma because at the time it was between $200 and $300 less. If you can get it for the same money that's an upside. And I definitely would never get rid of my DFA 100.

The Sigma 70 macro is my favourite APS_c portrait lens, it wasn't my first choice but 'd never get rid of it.

If I only had one though, it would be the DFA 100.

---------- Post added 06-28-19 at 01:40 PM ----------

QuoteOriginally posted by rr1736 Quote
I think the Sigma is a full frame lens I thought it was no longer made in K mount. The advantage to the 70 sigma would be that if you get a K1 at some time it would be useful on it also
They are both FF lenses.
For carrying in your camera bag for use when needed, the DFA 100 is WR and much lighter weight and smaller size.

Last edited by normhead; 06-28-2019 at 10:56 AM.
06-28-2019, 10:50 AM   #4

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The 100 is not too long to use for non-macro purposes. That's the one I would pick; it has more macro working distance than the 70, and is weather resistant.

The thread I linked below shows 3 portraits taken during a costume parade with the DFA 100 WR. I used a full frame K-1 and cropped later to remove distractions adjacent to the subjects. Your DA15 suggests you have an APS-C sensor, so you'll need to do less cropping in a similar use case.

Note that just about any macro lens will have a long focus throw from macro to infinity. That makes them less than ideal for general usage, but with practice and camera settings I don't get too much focus hunting with the DFA 100 WR.

For indoor portraits on APS-C, the 70 is likely a better focal length. 100mm is fine outdoors.

Coney Island Mermaid Parade -

06-28-2019, 11:01 AM   #5
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you can't go wrong with the Sigma 70 macro - it's a superlative lens... yes, it's big and chunky.... yes, the hood vs cap is a pain.... no, it's not WR....

but the photos it makes are really, really good....

I cannot comment on the D FA 100 Macro - my copy only arrived today, but it's smaller (dramatically smaller), has a better hood, is WR, etc...
06-28-2019, 11:24 AM   #6
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Don't forget the Tamron 90's if you want to split the difference from a focal length point of view.
06-28-2019, 11:37 AM   #7
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I have used my SMC Pentax-FA 100mm F2.8 Macro since the mid-90s with both film and digital cameras and have found it very useful for both macro and portrait work. With my K-3ii, the 150mm equivalent is even better for macro (harder to hand hold though-tripod recommended) and allows me to keep some distance between me and portrait subjects which is especially useful when shooting younger children. This is my go to portrait lens when I need sharpness in low light like at weddings. Don't think you can go wrong with the 100mm. Unless you need the WR and don't mind the extra weight of the FA version (about the same as the Sigma), consider finding a good used copy of the FA version for about 1/3 the price of a new one and trying it out. Just the thoughts of a long time fan of the 100mm prime.
06-28-2019, 11:48 AM   #8
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If you keep the 50, buy the 100. If you don’t, buy the 70. Buy both of you can.

06-28-2019, 11:49 AM - 1 Like   #9

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I only have a Pentax 100mm Macro F 2.8. I really like it, sharp lens, etc.

I use it as a candid portrait lens for available light, indoor 'portraits' of my fast moving, young grandson. He's pretty young, quite active and zips around at high speed...constantly.

The 100 macro on my K1 focuses fast and the image clarity is excellent.

I also use it at vintage car shows...I get some great perspectives by isolating interesting mechanical bits of vintage machinery...motorcycle and car engines, etc. Also use it a lot for flowers.

It's a very nicely constructed lens, aluminum barrel...IMO...a quality piece that for my needs seems versatile.
06-28-2019, 12:04 PM   #10
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I have a SMC Pentax D FA 100mm 2.8 Macro

I like it alot

both as a 1:1 macro and as a short telephoto

you get a longer working distance ( lens to target ) because it is 100mm as opposed to the 70mm lens

the aperture blades on the new one ( WR ) is different from mine and there is the WR but optically the DFA, FA and F 100mm F2.8 are the same, look at the " In Depth Review ":

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.

Read more at: Pentax-D FA 100mm F2.8 WR Macro Review - Specifications | Reviews

so if cost is an issue, you might consider the DFA 100mm F2.8 Macro lens, or FA 100mm F2.8 or F 100mm F2.8 macro lenses

Last edited by aslyfox; 06-28-2019 at 12:14 PM.
06-28-2019, 12:05 PM   #11
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A few months ago I started compiling a short list of macro lenses I was interested in. The current Tamron 90mm was at the top of the list. However, I recently picked up a Pentax F 100mm f2.8 Macro and love it. Best sharpness and colors of any of my lenses. I would imagine the D-FA 100mm has a similar optical formula, and the rave reviews here on the forum (except for autofocus?) speak to its outstanding quality.

Somethings to keep in mind about macro lenses for bug shooting, for instance. As lens to subject distance goes down, depth of field goes way down. I had to re-learn this with my 100mm Macro. At its closest focusing distance, 12", depth of field at f8 is 0.08" (just over 1/16") on my K-5IIS APS-C camera according to this calculator: A Flexible Depth of Field Calculator. At the same distance and aperture a 70mm lens would have a DOF of 0.2". Of course the bug would be smaller on the sensor, so it's a trade-off.

More distance equals more DOF regardless of lens focal length. I shoot some skittish bugs (butterflies, dragonflies, etc.) so I like the reach of the 100mm so I don't have to get so close to them. If your bugs sit still to have their portraits taken, you may prefer the 70mm for better DOF.
06-28-2019, 12:05 PM   #12
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You already received some good advice. I think that we , as a community, are lucky by so many excellent macrolenses around 70-100mm: Sigma 105 mm, Sigma 70mm, Pentax D-FA100 mm, Tamron 90 mm SP. All great lenses and you cannot go wrong with any of these.

Consider whether size and weight would be an issue. In the affirmative, the Pentax DFA100mm and Tamron 90 mm would be better choices because they are smaller and lighter. In the negative, you have plenty of choice.

My 5 cents.
06-28-2019, 12:11 PM   #13
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QuoteOriginally posted by Apet-Sure Quote
. . . The current Tamron 90mm was at the top of the list. . . . .
there is this review:

Tamron 90mm Macro vs Pentax 100mm WR: Review - Introduction | Reviews
06-28-2019, 12:28 PM   #14
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I don't know the Sigma 70, so can't comment specifically on that lens, but I used to own a Sigma 50mm macro, and it was an excellent lens. I sold it because I needed a macro lens with more working distance. Additionally I currently have the Pentax D-FA 100mm F2.8 WR Macro, fabulous lens. I got a it as a replacement for my FA-100mm F2.8 Macro which I'd had new from the early 90's and met a sad fate upon a concrete floor. Another amazing lens.

Personally, I don't think there is such a thing as a bad macro lens, at least that I've ever run across, so I don't think you can go wrong with either choice. It's going to be more about what other purposes you're going to use the lens for, as other's have mentioned above. For me, in the macro world, working distance is a factor. And I'm not looking to use my macro lens as a portrait lens, so my macro lens meets my specific needs. If I was looking today, I'd entertain looking at the Irix 150mm F2.8 macro (working distance!), if you're okay with a manual focus lens. It has excellent reviews, though apparently a bit of a beast.
06-28-2019, 12:46 PM   #15
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Thanks a lot for all those quick answers !

The Tamron 90mm never really interested me when comparing it to the Pentax 100mm, in terms of IQ, compactness, etc. And the difference of focal lenght is not that big to consider it as an intermediate option between my 28mm and the 100mm.

I shoot with a K-5ii, hence my fear of the 100mm being too long. I think the Sigma 70mm would be more versatile and make a better trio with my 15mm and 28mm... but I would loose working distance in the macro use, which is what I was primarily looking for. And the size and weight of the Sigma is really holding me back...
You mostly seem to lean toward the Pentax 100mm and it was originally my choice. Thinking in the long term, if I buy the 100mm and find the gap with the 28mm too important, I could complete with the 70mm Ltd for the portrait and landscape purposes when time and money come...
So many options!

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