Yes, but considering the 0.79 factor due to the larger sensor, the equivalent aperture of the Fuji 120mm lens is 3.16... That's not impressive... The Pentax 90mm lens has an equivalent aperture of 2.2... That's much better...

Well, such a lens could be used for portraits as well...

That's true. Perhaps Fuji decided to do an "all-purpose" telephoto prime that also offers good magnification (a-la the XF 60mm f/2.4).

The benefit of the 1:2 or even 1:3 only is that your effective aperture doesn't increase by two stops like it does on 1:1.
But macro is about 1:1 and it is just more required on larger format than it is with smaller format.

A 20Mpix 4/3" sensor puts 20Mpix on 17x13mm area, it is equivalent to 80Mpix FF sensor for 1:1. So calculate from that what it required from MF to get the same Mpix on 17x13mm area.

When it comes to operations on field, you really want to see the view as well yourself, why Live View technology is great as you can magnify the sensor view.

Still the cold truth is that most people don't need macro. A 1:3 or 1:4 is enough for most people at 4/3" format. Flowers, rings etc are usually larger than 17x13mm area. But for FF that is other case as 36x24mm area starts to be less effective for some. Still flowers and rings are not required on that so 1:2 or 1:3 is enough.
But going to MF, it again starts to be so that 1:2 or 1:1 is more critical than on FF, yet again...

@ Tommi K1

Re: "The benefit of the 1:2 or even 1:3 only is that your effective aperture doesn't increase by two stops like it does on 1:1."

That's not a benefit -- it's a limitation. At the same magnification, the effective aperture is the same. That is, a 1:1 lens at 1:3 magnification is no worse for wear than a 1:3 lens. The 1:1 lens simply offers you the *option* of a greater magnification should you want it. The disadvantage of 1:1 vs 1:3 will be size, weight, and price.

@GB for some it is advantage as they dont really need macro lenses but just good close-up lenses.
But you are right it is cost and limitation to have 1:1

@ZDman
Macro wasn't for film duplication.

The shirt, the jacket, and the watch in #9 look neutral enough to me. The face is reddish.

Who cares.... Of course if Fuji releases a extension tube to make it 1:1 then all is okay....
But otherwise, macro is 1:1 and so on...

Yes, but indeed it's no real "macro" with 1:2. The same thing Zeiss plays with some "macro"-lenses.

Hardly worth arguing about. It takes about 10 seconds for anyone to look at a lenses specification to check the maximum reproduction scale, without getting flustered because one manufacturer calls macro 1:3 and another calls it 1:1.

Surely the most important thing is to check the specifications before you buy ANYTHING, so that it is fit for purpose, and then use it for what it was designed to do? You'd have to be pretty daft to believe ANY advertising, in my opinion. The job of an advertiser, after all is to deceive the customer into thinking that something imperfect is perfect.

I am not holding myself out to be macro expert and I do not understand all of this 1:1 and 1:2 bidness. With my Canon FF cameras and lenses, I was able to get acceptably sharp and in focus images quite easily (focus stacking notwithstanding).

However, I have yet to master the macro 120mm on my 645z. Stopping down to f32, I still can't get an entire flower in focus setting up at the distances I have been used to with the former setup and having the flower cover the entire frame.

Rick - The reason why you get more depth of field (at a given aperture) with a Canon FF lens, than with a Pentaz 645 lens, is that the Pentax lens has a longer focal length (for a given angle of view).

Depth of field is a function of aperture, focus distance and focal length. You get the same depth of field at F8 with a 50mm lens, as you get with F16 and a 100mm lens (assuming same focus distance).

Depth of field has nothing to do with sensor size.

I am confusing no such thing. You are reading it wrong. You are an author. When I write, "sharp and in focus", those are two different conditions not necessarily related.

The problem on the table is how to get an object completely in focus with the 645z and a 120mm macro which seems to be the only macro lens in the Pentax 645 line-up. If you want to address this, fine. If the answer is, it can't be done, just say that and be done with it. If you have no experience with this setup, it's best that you do not answer at all.

@Rick Knepper
It depends on the subject. But if you can't get the subject in focus with the 120mm Pentax at F32 it will be the same with the Fuji and also all 35mm macros. They usually stop down only to F22.

So if you have subjects like this, focus stacking is your only option. But of course you can also focus stack using the pentax 645z.

Rick - No need to sound so defensive, I'm just trying to help.

If you are unable to get sufficient depth of field at minimum aperture, there are several other options open to you:
1) Increase the camera-subject distance, and crop down the image afterwards. This of course will reduce resolution and increase noise, but I'd assume that you are shooting on a tripod and at very low ISO, so it shouldn't be an issue. OR....
2) Switch to a shorter focal length lens, if you have one available, and if necessary use an extension tube to get the reproduction scale you need.
3) OR... Focus stacking.
Note: Shooting at minimum aperture is not good practice, as it introduces diffraction and greatly reduces overall sharpness.

No entoman, focal length has a minimal impact on the depth of field... What matters is the aperture, and the sensor size...

Entoman please get informed better: use the DEPTH OF FIELD CALCULATOR:
http://www.photopills.com/calculators/dof
The sensor size matters... And take into account that if you shoot with a 100mm instead of a 50mm, your subject must be at the double of the distance...

No you are wrong. I'm sure that DPR will be happy to confirm what I say - depth of field has NOTHING to do with sensor size. It is affected only by aperture, focal length and focus distance.

Try the test. Put an image on your computer. Now crop it down. Has anything about the depth of field changed? No, of course it hasn't.

"Now crop that image down to APS sensor size, or M43, or 1" or any smaller size. You still have the same image (or section of it). Nothing has changed.

The depth of field is NOT related in any way to sensor size, it is controlled by aperture, focal length and focus distance only."

The DOF is a "acceptance level of sharpness" that is measured on print that is 8x10", 300 DPI and viewed from 12" distance by person who has average 20/20 eye sight.

That is the measurement point. Every focal length, aperture, sensor size etc are calculated to that measurement point.

If you change the measurement point, then you change the DOF, even when you don't change anything in the camera.

If you have a digital file of image, you make a two prints of it. One is 8x10" and other is 4 times larger (32x40") then your DOF will be different on both prints when you view them from the same distance. But if you will look the 4x larger print from 4x further distance (48" instead 12"), DOF is same again.

So if you take a print, like 8x10 and you crop it by using a scissors, the DOF doesn't change when you are still looking that smaller print from 12" distance. But as the print is smaller, you naturally take the print closer, and it changes the DOF as the viewing distance has changed.

If you are not going to print on 8x10" 300DPI print and view it from 12" and have average 20/20 sight, then you are changing the DOF and every lens DOF range or DOF calculator are off.

And even then it is a lot of question about personal opinion "is this sharp" or not.

And it comes to different focusing methods even like a Merklinger method vs Hyperfocal Distance, where DOF is used differently in Merklinger to maximize the amount of detail in long distances that Hyperfocal Distance method can't resolve.

So before you even start to argue what changes the DOF in the camera, you need to define and agree on what output you are going to evaluation the DOF and who is doing the viewing.

Tommi - I didn't want to complicate matters or cause more confusion by mentioning that viewing distances/print sizes and personal eyesight etc also affect perceived depth of field, but you are of course right.

However, none of this is affected by sensor size. Crop down an image on your computer, it is exactly the same as "cropping" by using a smaller sensor. Nothing changes. UNLESS of course you enlarge the image, or get a lot closer to it, which is effectively the same as using a longer focal length lens.

Another test. Take a photograph with a wide angle lens. Crop it down to simulate the effect of shooting with a smaller sensor. It's still the same print, the depth of field has not changed.

Any photographic textbook will explain this. Depth of field is a function of Aperture, Focus distance, Focal length. But NOT sensor size.

Rick: Pentax sells a much more modern macro lens for the 645z: the stabilized 90mm f/2.8. It's a jewel (I own it and it is the lens I mostly use...)

"Try with a 50mm lens with a subject at 2m, or a 100mm with your subject at 4m, you get very approximately the same result..."

The DOF is identical when:
1) Using same format
2) Using same F-value (ie. f/5.6)
3) Subject magnification is same (ie person face covers 1/3 of the frame height)

Then the focal length has no effect for DOF, but the focal length controls the field of view how narrow the background or foreground is.

This is used by many portrait shooter who will get far more blurrier background with 200mm f/3.2 than you get with 50mm f/1.4 or 85mm f/1.8 when the subject magnification is same, even when the DOF is greater on 200mm because f/3.2.

So using the F-value and focal length, one can master the background blurring far more effectively than using F-value alone, yet get the subject better in focus (important in portraiture) so when you have ugly background and can't control it (sometimes not possible).

This all works because F-value is a ratio, not a diameter.

Tommi and idm - If you put say an 18mm lens on a little Panasonic with a tiny sensor, the depth of field will be identical to using the same lens on a full frame sensor, if the subject (focus) distance, and aperture (i.e. the F number, NOT the physical size of the lens iris) are the same.

I guess we can argue about this until the cows come home. I'll leave it up to DPR staff to intervene and explain the truth of the matter!

"Another test. Take a photograph with a wide angle lens. Crop it down to simulate the effect of shooting with a smaller sensor. It's still the same print, the depth of field has not changed."

Totally agree. As long the viewing setup doesn't change, cropping (sensor size) does nothing to DOF.

"Any photographic textbook will explain this. Depth of field is a function of Aperture, Focus distance, Focal length. But NOT sensor size."

Sure. This is the thing why it is as well silly to talk about "equivalence" and say that sensor size changes magically a lens properties, that are the DOF factors.

50mm lens at f/2.8 is 50mm + f/2.8 effect. It is not same as 25mm f/2.8 as focal length has changed. Regardless what sensor is behind.
But that changes the field of view, visual properties so one gets wider field of view (like larger print with same magnification) or narrower and it fools many as they want to compare identical image sizes (print sizes) instead different sizes.

Comparison: You want to take a similar photo using your Nikon D800, with two lenses, a 100mm and a 200mm... You use the same aperture: f/8
With the 100mm and your subject at 4m, the depth of field is 0.76m
With the 200mm and your subject at 8m, the depth of field is 0.75m
Almost the same result.

entoman: The DOF is same if you allow to do different image sizes (cropping).

Meaning if you take 25mm FF lens that you shoot at f/2.8 on FF, and then you move that lens to 4/3" and you shoot it as well without changing anything else than sensor size.
And then you make the prints. Now the FF print with same magnification is 2x larger, ie 40x30cm vs 20x15cm. The FF has wider field of view, but same DOF and all. The difference is just that the print size is 2x (width and height 2x).

But if someone now goes and enlarge the 4/3" print from 20x15cm to same 40x30cm, the DOF changes. Now the DOF on 4/3" print is shallower than FF print, even when both were shot at the same 25mm f/2.8 setting, same distance etc.
But everyone can see that FF has smaller magnification and so on wider field of view than 4/3" print, but physical print sizes are identical sizes (if we now just forget 3:2 vs 4:3) and the DOF is shallower on 4/3" print as it is enlarged more.
I think we are on same page in this

Yep, we are on the same page. You can't change the properties of a lens. It is indeed wrong for anyone to think that sensor size changes magically a lens's properties. But try telling that to some folk!

As for print sizes, they are fairly irrelevant, because small prints are typically viewed at much closer distances than posters (although some pixel peepers might enjoy getting very close and personal to a giant advertising billboard!)

@idM photography, yes: https://luminous-landscape.com/dof2/

The DOF is same, only thing you change really is the perspective and so on background magnification.

And sensor size matters: You have a 90mm f/2.8 for your Pentax 645z, and also a 90mm f/2.8 for your Nikon D800...
You want to take a similar picture, using the same f/2.8 aperture... With the Pentax and in order to take a similar photo, the subject must be closer because the equivalend focal lenth is 71mm
With the Nikon and the subject at 10m: depth of field is 2.1m
With the Pentax and subject at 7.9m: depth of field is 1.66m (shorter)

Tommi: very good link... I hope entoman had a look at it :)

Pinhole cameras are super easy when it is built with a zoom slider (mechanic to move the focal plane from the aperture, a aperture with swappable holes and a shutter with easy way to change speed of action.

The paper/film size can be changed as much as wanted, but DOF doesn't change.
If any of three individually or combined of focal length, aperture or camera distance is changed, DOF changes.

Technically nothing in the format size changes the DOF. Nothing.

It is the person own actions to change the other values, that changes the DOF. So instead just changing format, they alter focal length or aperture or distance or some other combination, changing everything else but not the format, the DOF changes.

It is just super easy to explain every possible function in the camera with the pinhole camera. If you allow person to change only single parameter/function in the pinhole camera, the format change is the only one that doesn't change DOF.

@Tommi I agree you can't just take the same photo using different focal lengths... So let's try the following example with totally equivalent lenses (90 mm for Pentax 645z is equivalent to 71mm for Nikon D800).

Nikon D800, 71mm f/2.8, subject at 4m: depth of field is 0.53m

Pentax 645z, 90mm f/2.8, subject at 4m: depth of field is 0.42m (shorter)

Depth of field with the Pentax will always be shorter (0.79 factor, which is the "focal length multiplier")

why 11.25 and 8.8875? I consider using the f/2.8 aperture in both cases

Tommi - I think we are banging our heads against a brick wall here! We've both tried to explain the facts, but they are not sinking in. I'm off to bed, as it's midnight here. Goodnight all.

entoman: you did not read well what Tommi wrote, and did not open the link he published: https://luminous-landscape.com/dof2/
You did not try the DOF calculator either... http://www.photopills.com/calculators/dof
Just make that small effort...

Ok entoman I hope you'll take photos with a nice bokeh using your cell phone, as sensor size doen't matter...

idm - You can't resist a last little dig can you?

The statements I made to you were indisputable scientific facts about depth of field and the factors that control it, which do NOT include sensor size.

As even you must be aware, I have never stated that "sensor size doesn't matter". In fact if you read my other posts you'll see that I regularly extol the virtues of larger sensors for their higher resolution, purer colour, increased dynamic range and reduced noise. And if you checked my profile you'd also see that I exclusively use full frame cameras.

Well, let's stop with scientific explanations... Here is a page you may find interesting, they shoot photos using wet plate collodion process, that's laaaaarge format. Have a look at the headshots, you will notice the extreme shallow depth of field...

http://www.imgrum.org/user/penumbratintypestudio/1772222559

idm - As a former industrial photographer who used Littlejohn Process cameras that accepted 30" x 24" sheet film, I'm already fully aware that large format cameras can under particular circumstances produce very shallow depth of field. The reason for this has nothing to do with the format, it is because of the focal length, aperture and focus distance (measured from focal plane to subject plane).

Instead of looking at images without supporting comparative images taken with other formats, apertures, focal lengths, subject distances etc, why don't you simply conduct the tests I have previously suggested. You'll then see for yourself that format doesn't affect depth of field, it is the OTHER factors that you are changing at the same time as you change format (e.g. focus distance) that change the depth of field.

You'll have to forgive me if I don't continue this discussion, patience is not my greatest virtue!

Turboff, you do understand that this crop of MF cameras is all about compactness and price.

It has very shallow DOF; did you look at those f/4 shots? In terms of DOF a MF f/4 is probably equivalent to f/1.8 on a 35mm camera.

Look at this f/8 portrait shot:
https://www.dpreview.com/sample-galleries/2749269086/fujifilm-gf-120mm-f-4-macro-r-lm-ois-wr-sample-gallery/6591702109
The eyes are in focus, but the nose is OOF at f/8.

The crop factor is 0.79x so not so much.

But people forgets that even on FF the best portrait f stop is around 5.6-11. you get plenty of blurry background but actual person face in focus from tip of the nose to the ears.

why shutter inside the lens? that's really interesting.

You appear to be confused as to what lens is being sampled. Or, you have poor composition skills.

Rick - Really?????

The lens being sampled is the Fujifilm GF 120mm F4 MACRO R LM OIS WR.
The only images taken at close distance are the flowers, and none of those images show focused fine detail across the full width of the frame.

My answer about the in-lens shutter quite obviously refers to the Hasselblad macro lens, as a response to a question about that lens by mmrezaie.

So what is your issue?

What is YOUR issue. I'm addressing the OP who is talking about a Hasselblad lens and is obviously confused. So now you are.