[Lowell Goudge]

As tryphon4 said, it's important to know that the minimum focus distance (MFD) is NOT the working distance. The MFD (like all distances marked on the lens barrel) is the distance from the sensor to the subject. The working distance (lens-front-to-subject) is a lot shorter.

For the Pentax 35 macro, the MFD may be 5.5" inches but the working distance at 1:1 is only a little more than 1" which makes lighting really hard and scares off everything besides flowers and mushrooms.

For the DFA 100/2.8 macro, the working distance is over 5" (the MFD is about 12") which gives a lot more room for lighting and is less likely to send tiny legs scurrying.

Ft his is why I said in my post we should consider working distance as roughly 2x the focal length.

[aslyfox]

This thread seems to speak about "minimum focus", but don't you think it would be a better idea to speak about "working distance"?

The working distance (WD) is the distance between the subject and the front of the lens.

WD is function of real focal length and magnification.

Here are some examples at 1:1:
Oshiro/Bresser 60mm 2:1 macro: 55mm
Tamron SP Di 90mm macro model 272E: 95mm
Panagor PMC 90mm macro: 127mm
Irix 150mm macro: 172mm

I have more examples at 1:1, 1:2 and 1:4 (other lenses with close-up or extension rings) if needed, you can read this page

As tryphon4 said, it's important to know that the minimum focus distance (MFD) is NOT the working distance. The MFD (like all distances marked on the lens barrel) is the distance from the sensor to the subject. The working distance (lens-front-to-subject) is a lot shorter.

For the Pentax 35 macro, the MFD may be 5.5" inches but the working distance at 1:1 is only a little more than 1" which makes lighting really hard and scares off everything besides flowers and mushrooms.

For the DFA 100/2.8 macro, the working distance is over 5" (the MFD is about 12") which gives a lot more room for lighting and is less likely to send tiny legs scurrying.

thanks

that is very interesting to know

I mistakenly used minimum focusing distance since that was in the reviews of the lenses.

I know better now

[Bruce Clark]

You have received may replies but I do recommend this video from B+H

You Tube

You Tube

[jddwoods]

I had the DFA 50 Macro and currently have the SMC DA 35 macro Limited and the DFA 100 Macro WR. I highly recommend the DFA 100 macro WR. It is so small and light it almost negates the light weight advantage of the shorter range Pentax options. It is the only one that is WR and for macro shooting the 100 mm focal length is a significant advantage for shooting anything that is not a static object. That includes small flowers that are blowing around in windy conditions. All three options are superbly sharp.

[UncleVanya]

A Guide to Working with Different Focal Lengths for Macro Photography

[swanlefitte]

A Guide to Working with Different Focal Lengths for Macro Photography

Thanks for that.

[monochrome]

It really depends whether you want a dedicated Macro lens or a very sharp traditional 35mm lens that has a decent MFD. The 35/2.8 Ltd. is an excellent, bright, colorful multi-use lens in its own right, that also has some Macro capabilities.

I have the DA 35 Macro Ltd and I crop nice images to simulate true macro. I also have the following very large FF Macro lenses which you might not find suitable hand held on a K-70.

• Vivitar Series 1 105/2.5 Macro - 1:1
• Vivitar Series 1 90/2.5 Macro - 2:1 plus 1:1 Extension
• FA and DFA 100/2.8 Macro - I bought the DFA in a fit of LBA and I plan to sell it. The K, M and A versions are excellent, and a lot less expensive.
• FA50/2.8 Macro - (possibly the sharpest Pentax lens that isn’t the FA*200/4 Macro)

[aslyfox]

A Guide to Working with Different Focal Lengths for Macro Photography

I agree, thank you

[richard0170]

I use a Tamron 72B. It is 90mm (135mm equiv .on APSc), f2.8 and does 1:1 on FF and therefore greater on APSc. It has great IQ. It is MF, which is better for macro, and because of this it is quite cheap and fairly easy to find. I use it for most of my macro work - but for certain subjects other lenses take precedent. So for flowers/funghi I prefer a 50mm macro, and for butter/damsel or dragon flies I use an old Tamron sp 300mm lens, which focuses surprisingly close, especially when mated to a 13mm extension tube.
For the cost of the 35mm macro, you could probably pick up both the Tamron lenses and an M 50mm f4 and maybe even a small speedlight for off camera use and have all your macro bases covered.
Having said all that, the 35mm macro is a superb general purpose lens, which just happens to focus closely, giving immense satisfaction in use and ownership -and would be an ideal companion for your K70 - just not for macro.
Another alternative for macro use are Raynox adaptors that screw into you filter thread. They come in various magnifications and will take you beyond 1:1, PKA extension tubes will also work with some (not all) DA lenses. You would have to focus manually, but that is better for macro anyway.

[Derek]

I use a Tamron 72B. It is 90mm (135mm equiv .on APSc), f2.8 and does 1:1 on FF and therefore greater on APSc. It has great IQ. It is MF, which is better for macro, and because of this it is quite cheap and fairly easy to find. I use it for most of my macro work - but for certain subjects other lenses take precedent. So for flowers/funghi I prefer a 50mm macro, and for butter/damsel or dragon flies I use an old Tamron sp 300mm lens, which focuses surprisingly close, especially when mated to a 13mm extension tube.
For the cost of the 35mm macro, you could probably pick up both the Tamron lenses and an M 50mm f4 and maybe even a small speedlight for off camera use and have all your macro bases covered.
Having said all that, the 35mm macro is a superb general purpose lens, which just happens to focus closely, giving immense satisfaction in use and ownership -and would be an ideal companion for your K70 - just not for macro.
Another alternative for macro use are Raynox adaptors that screw into you filter thread. They come in various magnifications and will take you beyond 1:1, PKA extension tubes will also work with some (not all) DA lenses. You would have to focus manually, but that is better for macro anyway.

Richard.

You've got my curiosity up. Is that "old tamron sp" a 54B?

The one shown on the SP website looks like it might be useful.

Derek

[pepperberry farm]

Richard.

You've got my curiosity up. Is that "old tamron sp" a 54B?

The one shown on the SP website looks like it might be useful.

Derek

no - the 72B is the later and last manual-focus 90mm SP lens that Tamron made and is distinctly different than the 52B or 52BB...

[swanlefitte]

I use a Tamron 72B. It is 90mm (135mm equiv .on APSc), f2.8 and does 1:1 on FF and therefore greater on APSc.

It's still 1:1 on 35mm sensor a 35mm subject will fill the frame and on a 24mm sensor a 24mm subject will fill the frame. Hence 1 to 1.

[lesmore49]

I have three macro lenses, a K F4 50, a DFA 50 F 2.8 and 100 Macro F 2.8 . All Pentax brand.

I like them all, but prefer the 100 as it gives me more focal length, for insects , as it's advantage is... it doesn't 'bug' them as much, with me being further away from them as a subject. Same thing with portraiture of people.

I've been intrigued by the 35mm Macro as I think it would also be good as a moderate wide angle, walk around lens. But on the other hand you would have to get fairly close to the live subject with the 35mm focal length. With insects or small animals I think you would spook them more easily, which is not a good thing, particularly with bees or hornets, which are interesting as subjects...or part of the deal if you like taking pix of flowers in outside gardens. Matters to consider.

Wish you well on your 'gas attack' .

[aslyfox]

. " . . . so I am ASKING FOR ADVICE! Please keep it short I don't want to be overwheled.

in a little more than 24 hours,( 08:42 01/18/19 ) the OP has gotten a lot of good advice

some of which agree

well done folks

[Derek]

no - the 72B is the later and last manual-focus 90mm SP lens that Tamron made and is distinctly different than the 52B or 52BB...

I was asking about the 300.