Macro with Mamiya RB67 and tubes

[Darryl Roberts]

I have a Mamiya RB67 Pro SD and am considering a Sekor macro c 140mm f4.5 and extension tubes for macro work (bobble heads).

Will I have razor sharp depth of field? I don't want that, it's not the look I'm going for.

Hopefully, you KNOW.

Thank you,

Darryl

 

[Trail Images]

Are you looking for more of an out of focus or soft focus look that the 150mm SF lens and inserts provide?

 

[MattKing]

For close focus work, the advantage of the 140mm macro lens for the RB lies mostly with its flat field performance - which probably won't matter a lot when photographing non-flat subjects like bobble heads.
The actual depth of field you will achieve depends almost entirely on the subject to film image magnification and the aperture you use - nothing more. The out of focus rendition ("bokeh") will vary from lens type to lens type, but the in-focus areas won't vary much.
Unless of course you are using a lens like the 150mm SF lens, which allows you to add aberrations in order to soften the image.
What is the size of the subjects you are photographing? That will tell us what magnification you are seeking?
FWIW, the 140mm macro lens actually gives you less maximum magnification than some of the other lenses. It is limited to half life size without an extension tube). IIRC, the maximum magnification (without extension tubes) can be obtained from the 65mm lens.
The 140mm lens gives you other advantages though. The aforementioned flat field performance, better working distances than the 65mm lens, and really nice performance as a moderately short telephoto (although I'm not sure that it is actually of telephoto construction).
When I wish to travel relatively lightly ( ) with my RB67, I use a 65mm and 140mm two lens kit.

 

[Deleted member 88956]

I have a Mamiya RB67 Pro SD and am considering a Sekor macro c 140mm f4.5 and extension tubes for macro work (bobble heads).

Will I have razor sharp depth of field? I don't want that, it's not the look I'm going for.

Hopefully, you KNOW.

Thank you,

Darryl

MattKing has pretty much explained the workings of DoF. I am somewhat perplexed by the meaning of "razor sharp depth of field". There is no such thing, it is always gradual and how fast it drops from sharp to soft has optical / physical dependencies Matt has referred to. A lot of it is in your control.

 

[Darryl Roberts]

For close focus work, the advantage of the 140mm macro lens for the RB lies mostly with its flat field performance - which probably won't matter a lot when photographing non-flat subjects like bobble heads.
The actual depth of field you will achieve depends almost entirely on the subject to film image magnification and the aperture you use - nothing more. The out of focus rendition ("bokeh") will vary from lens type to lens type, but the in-focus areas won't vary much.
Unless of course you are using a lens like the 150mm SF lens, which allows you to add aberrations in order to soften the image.
What is the size of the subjects you are photographing? That will tell us what magnification you are seeking?
FWIW, the 140mm macro lens actually gives you less maximum magnification than some of the other lenses. It is limited to half life size without an extension tube). IIRC, the maximum magnification (without extension tubes) can be obtained from the 65mm lens.
The 140mm lens gives you other advantages though. The aforementioned flat field performance, better working distances than the 65mm lens, and really nice performance as a moderately short telephoto (although I'm not sure that it is actually of telephoto construction).
When I wish to travel relatively lightly ( ) with my RB67, I use a 65mm and 140mm two lens kit.

Thank you, the subjects are 6 to 9 inches tall and I'd like to print 6x7s and 12x14s and have the frame full, make them look life sized.

 

[MattKing]

Thank you, the subjects are 6 to 9 inches tall and I'd like to print 6x7s and 12x14s and have the frame full, make them look life sized.

So, if you are photographing a 7.5" tall subject on to a piece of film that is 2.5" long (leaving a bit of space at either end), you are working at about 1/3 life size magnification. That is the maximum magnification you can obtain with the 140mm lens without an extension tube.
With a 65mm lens, you can focus closer, and obtain about twice as much magnification.
In either case, depth of field won't be large!

 

[John Koehrer]

With the focus closer of the 65, you're also going to be closer so lighting may be more challenging. There may also be a bit of distortion
that the 140 won't have with the longer working distance.

 

[narsuitus]

... the subjects are 6 to 9 inches tall and I'd like to print 6x7s and 12x14s and have the frame full, make them look life sized.

For close-up work with my RB67, I use a #1 extension tube (45mm extension).

Without the extension tube, at maximum bellows extension, my 140mm f/4.5 lens will fill the frame (portrait orientation) of a 21cm (8 inch) tall object.

With the extension tube, at maximum bellows extension, my 140mm f/4.5 lens will fill the frame (portrait orientation) of a 13 cm (5 inch) tall object.


Mamiya RB67 Close-up Kit by Narsuitus, on Flickr

 

[narsuitus]

@Darryl Roberts

Since you also shoot 4x5 inch large format, why not use that instead? At least you could use camera movements to control perspective and depth-of-field.

 

[Darryl Roberts]

So, if you are photographing a 7.5" tall subject on to a piece of film that is 2.5" long (leaving a bit of space at either end), you are working at about 1/3 life size magnification. That is the maximum magnification you can obtain with the 140mm lens without an extension tube.
With a 65mm lens, you can focus closer, and obtain about twice as much magnification.
In either case, depth of field won't be large!

Thank you. Will the 65mm suffer like a wide angle usually does when you approach a face?

 

[Darryl Roberts]

For close-up work with my RB67, I use a #1 extension tube (45mm extension).

Without the extension tube, at maximum bellows extension, my 140mm f/4.5 lens will fill the frame (portrait orientation) of a 21cm (8 inch) tall object.

With the extension tube, at maximum bellows extension, my 140mm f/4.5 lens will fill the frame (portrait orientation) of a 13 cm (5 inch) tall object.


Mamiya RB67 Close-up Kit by Narsuitus, on Flickr

Thank you for the wonderfully simplified answer.

 

[Darryl Roberts]

@Darryl Roberts

Since you also shoot 4x5 inch large format, why not use that instead? At least you could use camera movements to control perspective and depth-of-field.

I've considered it thank you.

 

[MattKing]

Thank you. Will the 65mm suffer like a wide angle usually does when you approach a face?

I expect you are referring to issues with perspective. For example, portraits where the nose appears larger and the ears appear smaller, and the head appears to have a great depth.
Those issues are entirely related to what the distance is between the subject and the film (the "working distance").
Yes, a 65mm lens will let you achieve higher magnifications, but it does that by allowing you to focus at a reduced working distance. And that affects the perspective.
It may be that you would prefer the flatter appearance that is associated with the perspective that comes from a longer working distance. Alternatively, you may wish to accentuate the depth of the subject, in which case you would prefer the perspective that comes from a shorter working distance.
Only you will know your preference.

 

[Darryl Roberts]

I expect you are referring to issues with perspective. For example, portraits where the nose appears larger and the ears appear smaller, and the head appears to have a great depth.
Those issues are entirely related to what the distance is between the subject and the film (the "working distance").
Yes, a 65mm lens will let you achieve higher magnifications, but it does that by allowing you to focus at a reduced working distance. And that affects the perspective.
It may be that you would prefer the flatter appearance that is associated with the perspective that comes from a longer working distance. Alternatively, you may wish to accentuate the depth of the subject, in which case you would prefer the perspective that comes from a shorter working distance.
Only you will know your preference.

Thank you very much for your help. Ill likely get both lenses to see my preference.

 

[Neil Grant]

I expect you are referring to issues with perspective. For example, portraits where the nose appears larger and the ears appear smaller, and the head appears to have a great depth.
Those issues are entirely related to what the distance is between the subject and the film (the "working distance").
Yes, a 65mm lens will let you achieve higher magnifications, but it does that by allowing you to focus at a reduced working distance. And that affects the perspective.
It may be that you would prefer the flatter appearance that is associated with the perspective that comes from a longer working distance. Alternatively, you may wish to accentuate the depth of the subject, in which case you would prefer the perspective that comes from a shorter working distance.
Only you will know your preference.

...the working distance won't just change the perspective. It will change the amount of background included and the distribution of d-o-f around the object of interest. Assuming a constant size for the object being photographed and aperture, the wide angle lens will show more b/g (if you are in a studio you may be unfortunate enough to 'go off the b/g'), the background will be more focused and areas forward of the point of true focus less well focused. The opposite occurs with the longer lens: less background included which is more defocused. Greater depth of field in front of the point of focus. Basically your combination of longer lens and increased working distance results in a more uniform magnification through object and it's background compared with a wide angle lens and reduced working distance.