Pentax 67 - Which lens allows for super tight portraits (shoulder-up, neck-up, etc.)?

[moodlover]

I was previously using an RZ67 w/ 110mm f/2.8 lens and it was brilliant, I could take neck-up shots and focus on the eyes with no problem. Now I am interested in purchasing a Pentax 67 since I had to sell my RZ67, and was always fascinated by the 105mm f/2.4 lens. Further research into it is quite disappointing as it seems I cannot use it to for close portraits due to its 3.25ft minimum focus distance. Does anyone know what I can do? I read the 90mm is about 2.25ft MFD so that would allow tighter shots, but I also read that it's bokeh quality is not as foggy and smooth as the 105mm's so that's unfortunate.

Do extension tubes diminish image/bokeh quality at all, if I put one on the 105mm?

Edit: Example of how close I want to be: http://i.imgur.com/uDcbw2r.jpg

 

[frank]

extension tubes

Even a diopter filter would work well for portraits because flatness of field is not necessary.

 

[markbarendt]

Extension tube would be my choice.

 

[moodlover]

Wouldn't an extension tube change the effective focal length?

 

[markbarendt]

Yes.

Lets put this in perspective though. Focusing you old RZ did the same thing.

Extending the bellows and adding extension tubes are equivalent.

 

[markbarendt]

As an aside the focal length and f/number marked on a lens are typically correct when focussed at "infinity". This is the point where the lens is closest to the film.

When you focus on subjects closer than infinity with a true "normal" lens, the lens has to be moved farther away from the film hence the effective focal length changes. This is easy to see on an RZ.

With internal focus lenses the elements inside the lens are rearranged to give the same effect. Moving the lens away from the film still works with these lenses, the trade of is that with the extension tube in place you can't focus at infinity.

(Yes, this description is over simplified.)

 

[bernard_L]

Wouldn't an extension tube change the effective focal length?

What is your definition of "effective focal length"? Is "effective" supposed have a special meaning, making "effective focal length" different from straight focal length? Anyway, following (optics) textbooks, a lens (simple or composite) has one focal length.

A lens with internal focusing is a different proposition of course. But this arose from extension tubes.

 

[Angelo di Mango]

I own the 100mm Macro for Pentax67 and it is great for portrait.
With my other lenses (i.e. 165mm) if i want to get closer, I use the shortest extension tube and that's enough.

 

[moodlover]

Lets put this in perspective though. Focusing you old RZ did the same thing.

Extending the bellows and adding extension tubes are equivalent. As an aside the focal length and f/number marked on a lens are typically correct when focussed at "infinity". This is the point where the lens is closest to the film.

When you focus on subjects closer than infinity with a true "normal" lens, the lens has to be moved farther away from the film hence the effective focal length changes. This is easy to see on an RZ.

With internal focus lenses the elements inside the lens are rearranged to give the same effect. Moving the lens away from the film still works with these lenses, the trade of is that with the extension tube in place you can't focus at infinity.

I didn't realize this before, but that's very interesting to learn! If extending the bellows is equivalent to adding extension tubes then I guess I'll go ahead and pick one up! Does the tube change the character of the light coming into the 105mm lens? That's really the only thing I'm worried about, losing the character the 105mm is known for but I'm sure this worry is unfounded. Lastly, do you know which tube I should get exactly to go from the normal portrait to neck-up portraits?

What is your definition of "effective focal length"? Is "effective" supposed have a special meaning, making "effective focal length" different from straight focal length? Anyway, following (optics) textbooks, a lens (simple or composite) has one focal length.

A lens with internal focusing is a different proposition of course. But this arose from extension tubes.

Basically, I realize adding a extension tube to the 105mm f/2.4 lens changes the focal length so it wouldn't actually be 105mm anymore, but longer (i.e. changing the look slightly).

 

[John Koehrer]

With the tube, there will be a slight exposure correction to be made..The chart I have on hand would be awkward to type(for me) on the computer, so here's a link to the appropriate information.
http://www.pentaximaging.com/files/manual/6x7_EXTENSION_TUBES.pdf)

Something to be aware of is exposure factor. It's similar to fliter factor where 2X=1 f stop compensation.

The other option mentioned above is close up lenses. Usually come it sets of three and need NO compensation.

 

[markbarendt]

I didn't realize this before, but that's very interesting to learn! If extending the bellows is equivalent to adding extension tubes then I guess I'll go ahead and pick one up! Does the tube change the character of the light coming into the 105mm lens? That's really the only thing I'm worried about, losing the character the 105mm is known for but I'm sure this worry is unfounded. Lastly, do you know which tube I should get exactly to go from the normal portrait to neck-up portraits?

Basically, I realize adding a extension tube to the 105mm f/2.4 lens changes the focal length so it wouldn't actually be 105mm anymore, but longer (i.e. changing the look slightly).

Couple thoughts.

You are not changing the glass, just the focus; right?

You didn't loose the RZ's 110mm lens character when you focused close before, right?

The perspective of any lens, of any focal length, is not determined by the focal length, but by the distance to the subject.

The angle of view is controlled by the effective focal length and film size.

 

[moodlover]

Ahh youre right, makes sense. Thanks so much for your input

 

[Poisson Du Jour]

The SMC Pentax 67 105mm or the ancient Takumar variant is very, very ordinary for what it is. It's popularity is down to the fact it is one of two 'standard' all-rounder lenses for the 67, the other being the squat 90mm f2.8.

The SMC Pentax 67 165mm lens, either in leaf-shutter (LS) form (f4) or the faster (and heavier) f2.8 non-LS form, is made for studio portraiture from a respectable distance (greater than 1.2 metres). The LS model is good for syncing studio strobes but its modus operandi can be confusing.

At the higher end of the scale in terms of money but a shorter focal length, the 75mm f2.8AL lens has also found a niche in portraiture, but this is not a lens to be sniffed at: it will show every fold, bulge and wrinkle if you're not careful! You might need to get hold of a few lenses on the 67 system in order to settle on just one as there are so many very good ones that cross-over in their purpose. Bokeh is irrelevant.

 

[markbarendt]

I think Poisson Du Jour has a great point about the lens length choice.

I'm also wondering though why not just replace the RZ with the 110mm lens you like?

 

[moodlover]

@markbarendt: I bought the RZ from eBay from some guy who claimed it had "sat in a closet for years" and it was only shooting at 1/400s for some reason when I tested it out. So when I went to get it inspected, they said the body was damaged internally as if someone dropped it. It was going to cost $320-500 to repair it so I figured I might as well switch systems while I can. I plan to shoot outdoors and the RZ makes it hard to get eye-level shots with the waist-level finder. I really didn't want to get rid of it because the pictures I was producing were beautiful

@Poisson: I'd love to check out the 165mm but I dont find any sample photos on the net with it, so it's hard to judge if I'd like the look or not. Why is bokeh irrelevant? A huge part of my portrait style is the mystical bokeh behind the eyes so the bokeh quality is important to me

 

[ColColt]

The 165 lens, whether the LS variety for studio work, or the 2.8 for outside would be my choice. The f2.8 will only give what the camera allows and that's 1/30th sec whereas the LS lens allows syncing up to 500th second.

http://www.ebay.com/sch/i.html?_fro...5+lens.TRS0&_nkw=pentax+6x7+165+lens&_sacat=0

 

[mweintraub]

I just got the 165mm LS and plan on getting some shots this weekend. Hope to have something to post next week!

 

[ColColt]

Here's two I did with the 165 LS some years ago...

Francis 007aa by David Fincher, on Flickr
KathyB013b by David Fincher, on Flickr