Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
09-21-2010, 10:02 PM   #46
Veteran Member




Join Date: Jun 2009
Photos: Albums
Posts: 1,679
oh goodness now that is one tough old dude!! hehehe...that is my point, we are candy asses these days compared to what people once did without a second thought...

My ex's dad is still spry and not quite as rugged as once was but he still can work all day if he paces himself at 85ish and would literially die if he did not work.

But seriously I laugh at those who worry about a couple ounces...but for some with health issues even that much can matter...but young guys and gals should not be worrying about "heavy"...it's heavy that keeps you stronger.

My maternal granddad was a good old German tool & die maker and he worked until he was in his late 80s loving every moment of it...as a kid I loved watching him machine up some do-dad whenever I got a chance to go to the shop with him as a kid.

but my response was your implication that the 180/3.5 was not a heavy lense...well to me it's not but to the vast majority around here it's a behemoth needing a few dozen native bearers to lug it around...to me it was just a lense but eventually I had to use it only on a monopod or tripod, I prefered the monopod. It now lives in Belgium with a buddy from another photo board.

I have a photo pal that shoots Canon who uses one of the plastic garden "bean poles" to steady his shots. He likes it because he can hold it between his hand and the body letting the pole take some of the weight AND can shift up and down fast because it's not attached to anything.

Oh, heck, how did I wander off into this side of the macro discussion? d'oh!! hehehe....

09-21-2010, 11:37 PM   #47
Site Supporter
Douglas_of_Sweden's Avatar

Join Date: Apr 2008
Location: Stockholm
Photos: Gallery
Posts: 3,347
QuoteOriginally posted by Digitalis Quote
Except when they are internally focusing lens designs E.G Sigma 180mm f/3.5 APO EX DG and Pentax FA*200mm ED IF Macro

I don't understand why people don't get why you lose so much light at closer focusing distances. In the darkroom, when we adjust the height of the enlarger we always have to recalculate the exposure because the light source is further away. When large format photographers extend the bellows further than the focal length we are using we have to calculate the light loss.
There are so much people here who never worked in a dark room and never used bellows.
09-22-2010, 04:02 AM   #48
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,312
QuoteOriginally posted by Douglas_of_Sweden Quote
There are so much people here who never worked in a dark room and never used bellows.
Welcome to the age of digital only photographers, who for the most part have also never read a single book on photography, but rely on forums like this one to answer questions
09-22-2010, 04:51 AM   #49
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 8,535
the Digital age indeed, and all the books on photography now have unbearably pretentious titles such as "master flash photography in 10 mins" and "master B&W printing techniques"

I really enjoyed working in the darkroom. the tactile sensation of holding a frozen moment in my hand.

09-22-2010, 06:42 AM   #50
Site Supporter
GeneV's Avatar

Join Date: Oct 2008
Location: Albuquerque NM
Photos: Albums
Posts: 9,761
QuoteOriginally posted by Lowell Goudge Quote
for the most part have also never read a single book on photography, but rely on forums like this one to answer questions
...including the equipment manual, but that was another thread.
09-22-2010, 10:39 AM   #51
Veteran Member
Laurentiu Cristofor's Avatar

Join Date: Nov 2009
Location: WA
Photos: Albums
Posts: 3,044
QuoteOriginally posted by Douglas_of_Sweden Quote
There are so much people here who never worked in a dark room and never used bellows.
Or wet collodion plates.
09-22-2010, 11:18 AM   #52
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
They never worked a darkroom -- that's understandable, darkrooms are small and smelly.

They've never even been in a darkroom -- I grew up in my dad's, it's always been home to me.

They've never read a photo book -- to me, this is incomprehensible. The first camera I bought from earnings, ie my own hard-won cash, not just a gift Brownie, was some forgotten German fixed-lens rangefinder I got used at Brooks Cameras in SF around 1969. Film and processing cost money, so I studied carefully before spending more. I memorized the camera manual, took the camera apart as much as I could and studied each part and function carefully, read library books on camera technicalities, etc. I'd been raised photographically so I already knew composition, aesthetics, light, shadows, forms. I carefully read the data sheets included with each roll of film, memorized their characteristics, etc.

Each new piece of gear -- body, flash, camera / enlarger lens, developer, etc -- meant more technical reading, as well as accumulating many general and specialized books. They're still in front of me: the Petersen Photographic series, the Time-Life Library, THE EYE OF EISENSTAEDT, PHOTOGRAPHING THE NUDE, Ansel of course, LIGHT AND VISION, Blaker's FIELD PHOTOGRAPHY, Linton's PHOTOGRAPHING NATURE, THE ZEN OF PHOTOGRAPHY (oops, I lost that one), and sheafs of tech notes from Kodak etc. And filling my brain with studied images from Renaissance perspective to Kirlian zaps. These were what it took to learn the subject. And I'm still learning. I haven't memorized the K20D and 360F manuals -- didn't memorize the OS-370 manuals either, digital has too many details -- but I ask myself questions and research as much as possible before I raise questions in forums. I asked nobody about what dSLR and lenses to buy. I studied and analyzed and decided.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _

But not everyone studies, so we get questions about photographic basics, and we who study answer those questions over and over. And we sometimes get more involved questions, like on the optics of macro lenses (the subject of this thread), that maybe require more study to answer fully, and we all learn. Of COURSE aperture shrinks with extension -- except for those lenses designed to keep constant apertures at all magnifications. Who'd'a'thunk it? I've learnt a tremendous amount here, and been forced to learn much more to stay current here. The process never ends.

QuoteOriginally posted by Laurentiu Cristofor Quote
Or wet collodion plates.
Wet plates are still in use by a few maniacs, er I mean enthusiasts. The hard part is shooting macro with them.

Last edited by RioRico; 09-22-2010 at 11:24 AM.
09-22-2010, 06:30 PM   #53
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,312
QuoteOriginally posted by Digitalis Quote
the Digital age indeed, and all the books on photography now have unbearably pretentious titles such as "master flash photography in 10 mins" and "master B&W printing techniques"

I really enjoyed working in the darkroom. the tactile sensation of holding a frozen moment in my hand.
You forgot digital photography for dumbies

09-22-2010, 07:06 PM   #54
Veteran Member




Join Date: Jun 2009
Photos: Albums
Posts: 1,679
QuoteOriginally posted by Lowell Goudge Quote
You forgot digital photography for dumbies
Are those relatives of GUMBY?

....ya DUMMY you....dummies to the left dummies to the right...dummies everywhere....snickersnicker....

BTW, I too miss the darkroom but haven't been near one since my freshman year of college because, well, like others mentioned it was too costly and too easy to disappear into the darkroom because, well, it was so peaceful and relaxing in there. I think that is what I really enjoyed, the peace and quiet even when working with others in there with you...something about the low light and all I suppose, but I could get away from everything in there.
09-23-2010, 09:44 AM   #55
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,312
just to go back a few pages, some people have posted about lenses which had the aperture change when focusing.

I would be interested in having anyone who has one of these to answer a single question.

How big was the front element?

The reason I am asking is that unless the front element was big enough in diameter to allow an unrestricted natural aperture of F1.4 or something like that, no matter what a lens maker does with the diaphram, the lens can never ever get faster than the focal length over the front element diameter.

As for someone who posted about using close up lenses, the reason they work a little better is that they actually modify the focal length of the lens.

If you take a +4 diopter close up lens, and add it to a 50mm lens it actually makes it a 41mm lens, so yes it gets "faster"
09-23-2010, 10:22 AM   #56
Inactive Account




Join Date: Oct 2007
Location: Brisbane, QLD, AUS
Posts: 3,262
Maximum aperture = focal length / objective lens diameter.

As it is, was and evermore shall be.
09-23-2010, 10:44 AM   #57
Pentaxian




Join Date: Feb 2009
Location: Arizona
Posts: 868
QuoteOriginally posted by newarts Quote
A non-internal-focus (old fashioned) lens's focal length and aperture do not change as you move the lens towards or away from the camera to bring things into focus.
Actually the focal length does change when the lens is moved away from the film/sensor. This is because, as you focus closer, the light rays from the object diverge more (as opposed to parallel at infinity) and enter the lens in a diverging fashion, causing a longer focal length than when at infinity.
09-23-2010, 10:45 AM   #58
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,312
QuoteOriginally posted by lithos Quote
Maximum aperture = focal length / objective lens diameter.

As it is, was and evermore shall be.
No, this is not quite correct. especially in zooms, as an example, my series 1 70-210 F3,5 has about a 60mm front element, so at 210mm it is truely limited by the diameter of the element, BUT at 70 mm with that diameter front element, it could be an F1.2 lens, but isn't. the internal optics and aperture placement ensure it is a constant F3.5

This is why I asked the question about nikon lenses that had an aperture diaphram that changed size with focus, I was curious to know if this was applied to the wide open case, and if the lenses truely held maximum aperture all the way to 1.1 or not.,
10-03-2010, 05:25 PM   #59
Forum Member
Super A-wesome's Avatar

Join Date: Sep 2010
Posts: 94
QuoteOriginally posted by Banjo Quote
I now remember reading about this somewhere, but it obviously didn't really register.

So, last week, I put a roll of film past a Macro lens I was using (Elicar 2.5/90 Macro), but accidentally forgot to reset the ISO on the camera (an OM2n) and had the ISO set to 200 for a 400 ISO film.

I didn't realize I had done this until about half-way through the film, when I reset it to 400.

I wondered how my shots would look overexposed by 1 stop (compared to my usual practice)

Well, actually, they came out very well.

Now, I see that -using the above formula- for a magnification of .25x (which is about what I was using, photographing flowers), I should be allowing a +1 stop exposure.

This is very interesting, and I will try to adopt this in my future technique.

Thanks
Actually, (assuming your camera has TTL metering) this correction is not required. The decrease in f/stop is compensated. Now, assuming you are using color print film, the reason your shots didn't come out looking overexposed is that print film has a very high tolerance for over/under exposure, and the one-hour machines can make good prints from negatives that are -1 to +3 stops from the correct exposure.

Hope this helps
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
distances, f2.8, k-mount, lenses, macro, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
1:1 macro lenses ismaelg Pentax SLR Lens Discussion 25 06-01-2010 04:37 AM
Macro lenses.. nikonnoah Pentax SLR Lens Discussion 10 09-19-2009 08:28 AM
Macro lenses -- AF or MF? K-9 Pentax SLR Lens Discussion 19 08-13-2009 08:02 PM
For Sale - Sold: Everything Macro: Bellows, Ext. Tubes, Macro Lenses MikeDubU Sold Items 12 03-14-2009 07:10 PM
D-FA 100/2.8 Macro vs other macro lenses? jankok Pentax SLR Lens Discussion 12 10-25-2007 09:01 AM



All times are GMT -7. The time now is 10:24 PM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top