RB67 APO: 250 or not 250? That is the question.

[stradibarrius]

The 250 is like a 125mm in 35mm format correct? That is a pretty good focal length for taking photos of my violins to post on my web page.
I have a Sigma 10-20mm WA for my Nikon D-80 and it is a very good lens but I don't use it very often so I wonder how much use I would get from a RB 50mm lens?

 

[keithwms]

Stradibarrius, The shorter focal lengths may prove useful for macro shots of your instruments. What you will quickly realize is that when you use a longish lens (like the 250) you need a*lot* of bellows extension to get high-magnification shots, and your depth of field will be extremely shallow. The built-in bellows on the rb won't get you anywhere near 1:1 with a 250; for that you'd need extension tubes. (Extension tubes are fine, and inexpensive, I am just saying....)

For macro I think you will find that lenses equal to or shorter than 127 will become your favourites. If you don't mind distortions too much (or are willing to correct them electronically) then the really short focal lenths like 65 or 50 or even 37 (fisheye) can give you some very interesting macro options. I use the 65 and 37 quite often for that kind of thing.

Most folks will use the 50 for architecture, interiors, that kind of thing. Definitely not portraiture! Anything shorter than ~127 would be an unconventional choice for portraiture.

 

[Q.G.]

Stradibarrius, The shorter focal lengths may prove useful for macro shots of your instruments. What you will quickly realize is that when you use a longish lens (like the 250) you need a*lot* of bellows extension to get high-magnification shots, and your depth of field will be extremely shallow.

Not necessarily.

When you find the extra extension needed to get the same scale with the longer lens, you will find that not just the image scale, but also the depth of field is exactly the same.

When using the same amount of extension, the longer lens will indeed have less depth of field. But not just the depth of field then is different: it will also produce a higher image scale.

Focal length does not determine depth of field.
Scale (or magnification) and f-stop do.

 

[keithwms]

??? I mentioned high magnification in my post...

 

[Q.G.]

??? I mentioned high magnification in my post...

Yes.
And when comparing focal lengths, shorter focal lengths offer no advantage, they will not prove more usefull, as far as depth of field is concerned. High magnification or low magnification, as long as it is the same magnification, depth of field is the same too.

 

[keithwms]

QG I agree that at the same magnification, the dof is the same. I see that my sloppy sentence construction implies the link between focal length and DOF.

But.... back to [what I thought was] the point of my post: you'll need a lot more bellows draw to get to typical macro magnifications (say ~1:1) with the longer lens. Most folks do not use the longer lenses for macro, for this reason.

Mind you, Stradibarrius, sometimes the distance between lens and subject comes in handy (bug macros!), but for macros of instruments, I think a 127 or shorter will prove very useful.

Concerning working distance, macro with the fisheyes can be quite hilarious: with one additional extension tube, you can easily get to the point that the object in focus is literally touching the lens. Probably not what you want for instrument photography But on the other hand, if you don't mind really big perspective distortion, the short lenses can give you some very dramatic views.

There are of course "dedicated" macro lenses in the rb and rz lineups, but... a lot of folks are very happy at all magnifications with the non-specialized lenses, for product shots.

 

[Q.G.]

Indeed: longer lenses are generally not fun to work with. Too much extension needed.

There is the thing about perspective too. In 'regular' photography, there is a relation between sizes of objects, distances between them, and focal length and working distances that yield the best looking perspective. (You could take a picture of a happy family gathered around a table, with the birthday boy about to blow out the candles on the cake, from half a mile away using a long lens. But you will not get that cosy 'taking part in the fun' look).

So when object sizes get smaller, shorter lenses not only make it easier to achieve the required magnification, but also produce better looking pictures. Round about 1:1 a 'standard lens' will be very good to use. With larger magnifications, even shorter lenses will be very usefull.

 

[jaimeb82]

I have a pile of lenses for my rb, and the one that gets the least use is the 250. I do however like putting it on with a 2x converter and watching the neighbors tv from a block away....LOL --- I would tend to buy another 180 or 150 in search of better quality. maybe even look hard for a 140

50/65/90/127/150/180/250

I just got a 250mm and a 2x converter, I put everything together and couldn't focus anything inside of my house, I am going to try outside tomorrow morning, but since you have this set up, is this normal, do I need to point at a subject really far away?

 

[keithwms]

Get some extension tubes and you'll be able to focus much closer.

 

[2F/2F]

I just got a 250mm and a 2x converter, I put everything together and couldn't focus anything inside of my house, I am going to try outside tomorrow morning, but since you have this set up, is this normal, do I need to point at a subject really far away?

As I have learned on APUG, you should be able to focus at the 250 lens' normal close focusing limit even with the doubler.

Focusing close on that camera with a long lens is a situation in which you will want to make sure that the weight of the lens is adequately supported by a hand, a monopod, or the purpose made Mamiya lens holder. Also, if not using flash as your main light, you will benefit from using MLU.

 

[jaimeb82]

As I have learned on APUG, you should be able to focus at the 250 lens' normal close focusing limit even with the doubler.

Focusing close on that camera with a long lens is a situation in which you will want to make sure that the weight of the lens is adequately supported by a hand, a monopod, or the purpose made Mamiya lens holder. Also, if not using flash as your main light, you will benefit from using MLU.

Something must be wrong, I was at home about 10feet from a lamp inside the living room and couldn't get a clear image, in fact it was really out of focus, not even, the bellows were not extended. You are right about the weight, the thing with the 2x extender looks like a weapon of mass destruction.

 

[jaimeb82]

Get some extension tubes and you'll be able to focus much closer.

What's an extension tube, I have a 82mm 2x extension right now.

 

[keithwms]

I guess the "2x" you are referring to is a teleconverter, not an extension tube. Some people confuse the issue by referring to extension tubes as "tele-extenders." An extension tube is just an empty tube, no glass inside, that you put between your lens and the camera body. It simply extends your bellows draw, thus allowing you to focus much more closely. It is a very good and inexpensive way to get into macro. Extension tubes are very inexpensive and don't degrade contrast and sharpness like a TC does.

With a 360 and a few extension tubes, I recall being able to focus down to a few feet. A cool thing about the rb is that because it's built like a tank and has a *very* robust lens mount, you can just slap a lot of extension tube on there and it'll look hilarious and weight a ton but it's still stable and the lens mount doesn't get torqued and bent. I do agree with the previous comments that supporting the lens and tube is a good idea, long term. But my experience is that it isn't necessary for short-term things; mind you I tend to shoot macro stuff directly downwards and not at odd angles that would torque the lens mount.

 

[jaimeb82]

thanks for clarification, I have an extension tube, not 2x but Number 2. I totally mix those two objects, the teleconverter used to increase mm in a lens and the extension tube for macro. That's why I saw everything out of focus. Can't wait to test the lens, I bought a 360mm and a 250mm arrived. Seller from that big auction site wants me to send everything back, I am just going to keep it, I wanted the 360mm but better a 250mm than keep looking again.

 

[panastasia]

I have a pile of lenses for my rb, and the one that gets the least use is the 250. I do however like putting it on with a 2x converter and watching the neighbors tv from a block away....LOL --- I would tend to buy another 180 or 150 in search of better quality. maybe even look hard for a 140

50/65/90/127/150/180/250

I have all the lenses mentioned here except the 50 & 127 and I also have the 140 and 360 + 2x converter. The lenses are all KL series. By my own observations the 180 seems to produce the sharpest images of any of the others, if you want me to call it, but the difference is insignificant as far as I'm concerned. My most used lenses are 65/140/180/360. The one that gets the least use is the 250 - I use it occasionally for close portraits indoors but the 180 does pretty much the same with a little cropping of the negative. If you like the flat look of distant views and peoples faces, as I do, the longer 360 is better for that effect. The 250 seems to remain in some sort of dead zone for me, and it's also the heaviest one of the bunch (the 180 is the lightest) which is another reason I leave it behind when out and about with 3 lenses. I'm only an expert on my own opinion.

Paul

 

[2F/2F]

Something must be wrong, I was at home about 10feet from a lamp inside the living room and couldn't get a clear image, in fact it was really out of focus, not even, the bellows were not extended. You are right about the weight, the thing with the 2x extender looks like a weapon of mass destruction.

Your bellows should extend way out if you are focusing on something inside. That is, unless you live in a mansion. If they are all the way in, you are focused on "infinity".

 

[jaimeb82]

no mansion here in NYC, shoe box instead, I didn't try extending the bellows all the way out. Thanks for the clarification/explanation, so that's what infinity means! all this time I was wondering about the infinity thing in sentences like, "then focus into infinity...bla...bla".

 

[stradibarrius]

I have about decided that the 65mm and the 180mm would be more useful to me. I currently have a 127mm.