Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
11-13-2011, 09:59 PM   #331
Veteran Member
Don From The Radio's Avatar

Join Date: Jul 2011
Location: Delaware
Photos: Gallery | Albums
Posts: 344
Many of the older M and A series lenses were so good optically that it's tough for new glass to compete. But I really was having problems getting focus right, even with the K200D's focus indicator. Of course most of that has to do with taking more than a few hockey sticks to the eye as a teenager.

11-13-2011, 10:03 PM   #332
Pentaxian
wolfiegirl's Avatar

Join Date: Oct 2011
Location: Outside of Canberra, Australia
Photos: Gallery
Posts: 4,049
Original Poster
Ok all confirmed. The guy's coming by tomorrow with his Jups. This is $240 we're talking about here..... *gulp* quick! someone talk me out of it!!!!
11-13-2011, 10:13 PM   #333
Loyal Site Supporter
wizofoz's Avatar

Join Date: Apr 2009
Location: Melbourne, Outer east.
Photos: Gallery | Albums
Posts: 1,654
wolfie, you seem to be lacking a couple of important basics. Forgive me if I am reapeating things you already know, but here goes...

Aperture = the size of the hole that lets light through to the sensor or film.
Tv = time value, the amount of time the shutter is open to allow the light onto the sensor or film
ISO = either the sensitivity of the film to light, or, more aptly for these digital days, the amount of AMPLIFICATION of the signal the sensor makes when exposed to the amount of light (aperture) for a given time (shutter speed) to acheive a desired exposure level. In other words, this is electronic multiplication of the signal to acheive a desired outcome.

[Digital noise is the result of this amplification. The more advanced the sensor, the better the signal to noise (S/N) ratio is. A camera like the K-5 has one of the best and cleanest sensors going around because when the signal is amplified, the electronics of the camera ensure that the output image does not have the inherent grain/noise of lesser sensors. Does this make sense?]

In other words shutter, aperture and ISO are interrelated. Exposure value (EV) = a combination of all three in unison. If you change one of the paramenters, you must adjust one or both of the others to acheive the SAME exposure.

for example, lets say you have your ISO set to 100, your lens set to F4 and the time value returned by the camera for correct exposure = 1/100 sec. 1/100th may not be a fast enough shutter speed for your desired intent (say freezing a moving object) so you want to decrease the shutter speed to 1/200th (half the time) to compensate you would either open the aperture by ONE STOP to F2.8, or increase the ISO to 200, either would result in the same exposure. If you want and even faster shutter speed you would open up the aperture even further. Say 1/400th and F2.0. But wait! the lens is not 'fast' enough to get to F2.0, because F2.8 is its max aperture. What then? Well thats when you increase the amplification factor by adjusting the ISO. so now we set ISO to 200, the lens to F2.8 and the shutter to 1/400th and have the same exposure value, but a different looking image because the shutter was open for a shorter amount of time.

Why is 1.4 important in photography? Because 1.4 is the square root of 2 (near enough). The formula for the area of a circle is, as you probably know, Pi x r squared.

If you want to increase or decrease any particular aperture value to half or double the amount of AREA, (and therefore half or twice as much available light) one divides (or multiplies) the aperture by 1.4. Thus the aperture sequence is F1, F1.4 F2, F2.8 F4, F5.6 etc. If you grab a calculator and do the math (1x 1.4 = 1.4, 1.4 x 1.4 = 1.96, etc.) you will find that with a little rounding, this sequence works.

You don't generally need to do this mental arithmetic, you only need to know if your lens or camera changes aperture and speed in 1/2 stop or 1/3 stop steps. If it is half stop incremants move it two clicks to change settings by a FULL STOP, if it is giving you more fine control in 1/3 stop increments, move it by 3 clicks for the same result.

Just a few thing to shed a little 'light' on your new found passion.
11-13-2011, 10:21 PM   #334
Pentaxian
wolfiegirl's Avatar

Join Date: Oct 2011
Location: Outside of Canberra, Australia
Photos: Gallery
Posts: 4,049
Original Poster
Thanks Wiz. Yeah I've been spending a lot of time trying to figure out all the aperture stuff. The manual really was too advanced for me to understand. It took me two days straight of reading to figure out aperture and depth of field. It's difficult for me because I'm more of a visual person and numbers and figures always put me into a tail spin. It requires a lot of energy to figure it all out and I must admit I'm lazy

Yet I still know that I'm missing gaps here and there :blush: So your explanation does help. Hopefully if I reread things often enough they will sink in. I am aware that there is a relationship between the ISO, f stop and speed. It's just trying to remember the sweet spot and how to get there that's the problem. But that's nothing that more practice out in the field won't solve, right? That and rereading everything I can on photography...

11-13-2011, 10:29 PM   #335
Loyal Site Supporter
wizofoz's Avatar

Join Date: Apr 2009
Location: Melbourne, Outer east.
Photos: Gallery | Albums
Posts: 1,654
Any time you have a question just ask, wolfie. As you have found, this is a very helpful place. And besides I'd rather write diatribe about lenses than actually work for a living
11-13-2011, 10:30 PM   #336
Pentaxian




Join Date: Jan 2010
Location: Vancouver, BC
Posts: 1,421
QuoteOriginally posted by wolfiegirl Quote
Ok all confirmed. The guy's coming by tomorrow with his Jups. This is $240 we're talking about here..... *gulp* quick! someone talk me out of it!!!!
What's in the lot? How did your Tamron SP bids go?
11-13-2011, 10:32 PM   #337
Pentaxian
wolfiegirl's Avatar

Join Date: Oct 2011
Location: Outside of Canberra, Australia
Photos: Gallery
Posts: 4,049
Original Poster


there's so much information already written, i always feel hesitant to ask. i figure if i have this question, someone else must have asked in the past too! and i don't want to clog up the forum with questions that have already been asked dozens of times. i've been on many forums where the keepers come storming out and go "search button is your friend". so i tend to do that and only start asking questions when i really get stumped.

thanks for the encouragement wiz. now to further your explanation... depth of field. there's a fine line isn't there between having the lens fully open and high speed and getting a decent depth of field?
11-13-2011, 10:34 PM   #338
Pentaxian
wolfiegirl's Avatar

Join Date: Oct 2011
Location: Outside of Canberra, Australia
Photos: Gallery
Posts: 4,049
Original Poster
QuoteOriginally posted by excanonfd Quote
What's in the lot? How did your Tamron SP bids go?
Kiev 4 body - 1984 (plus original case)
Helios 103 - 53/1.8 - 1984
Jupiter 3 - 50/1.5 - 1963
Jupiter 9 - 85/2 - 1968 <--Note that the focusing on the 85/2 is a little stiff but apparently this is not uncommon
Jupiter 9 Finder - no date
Jupiter 11 - 135/4 - 1970
Jupiter 12 - 35/2.8 - 1985
Multiple Turret Finder - no date

All lenses and finders have their original plastic cases.

He's asking $240 for it and coming by tomorrow for me to inspect. If it's good I'm thinking I might wear a low cut top....

The tammy bids all fell through, but I have another 3 on the burner. *shakes head* You'd think after calculating how much I'm in the red I'd stop.... But those all sound like nice lenses to me? Even though I already own a Jup 39 135...

Note: I've cross posted this Q at the soviet lens club but so far no replies

I'm assuming all the lenses will go on the kiev. The kiev has the same m42 mounts right??


Last edited by wolfiegirl; 11-13-2011 at 10:44 PM.
11-13-2011, 10:35 PM   #339
Loyal Site Supporter
wizofoz's Avatar

Join Date: Apr 2009
Location: Melbourne, Outer east.
Photos: Gallery | Albums
Posts: 1,654
hey wolfie, remeber I told you I bought the DFA 100mm WR the other day? Well I changed that with the co-operation of the vendor to be a the 60-250. Just a slight upgraqde in cost/performance factor and I figured the 60-250 would make a great trvel companion.

But then this afternoon I found another copy of the 100wr... and. I. couldn't. resist.
11-13-2011, 10:40 PM   #340
Pentaxian
wolfiegirl's Avatar

Join Date: Oct 2011
Location: Outside of Canberra, Australia
Photos: Gallery
Posts: 4,049
Original Poster
QuoteOriginally posted by wizofoz Quote
hey wolfie, remeber I told you I bought the DFA 100mm WR the other day? Well I changed that with the co-operation of the vendor to be a the 60-250. Just a slight upgraqde in cost/performance factor and I figured the 60-250 would make a great trvel companion.

But then this afternoon I found another copy of the 100wr... and. I. couldn't. resist.

bwahahahhahaa

we are all sick, sick sick.........
11-13-2011, 10:48 PM   #341
Loyal Site Supporter
wizofoz's Avatar

Join Date: Apr 2009
Location: Melbourne, Outer east.
Photos: Gallery | Albums
Posts: 1,654
QuoteOriginally posted by wolfiegirl Quote


there's so much information already written, i always feel hesitant to ask. i figure if i have this question, someone else must have asked in the past too! and i don't want to clog up the forum with questions that have already been asked dozens of times. i've been on many forums where the keepers come storming out and go "search button is your friend". so i tend to do that and only start asking questions when i really get stumped.

thanks for the encouragement wiz. now to further your explanation... depth of field. there's a fine line isn't there between having the lens fully open and high speed and getting a decent depth of field?
Yeah the search function is a good way to start, but then again, repetition is good as it makes the lessons stick.

Depth of field is related to

a, the size of the sensor
b, the length of the lens
c, the area of the aperture

a, size of the sensor (or film stock) gives greater depth of field when it gets smaller (for reasons I cannot bring to mind at the moment.) Small sensors, such as are found in P&S camera give more depth to the 'in focus' field, which makes it easier to get everything in the pic in focus when doing party snap shots, etc. The larger the sensor the shallower the depth of field. so our APSC sensor gives a far narrower DOF than the P&S, but a full frame sensor will result in even finer DOF and then a medium format sensor would give even less DOF for a given focal lenght and aperture.

b, length of the lens. As someone said earlier, a wide angle lens gives less 'compression' to the image than a telephoto. So a pic taken with a 200mm F2.8 lens will have razor thin DOF compared to say the DA14 at the same aperture.

c, the narrower the aperture (higher number) the greater the DOF. This is to do with the rules of optical science, which is beyond my ken, and beyond what one actually needs to know to take a good photo, and beyond the scope of this answer. Just remeber, the bigger the F number, the bigger the 'in focus area.

So when used in conjuction, a fast, long lens on a large sensor will give razor thin DOF, but is a bugger to get in focus. A wide angle lens on a small sensor is a snap to focus because everything from near to the far distance appears sharp.

This is why P&S cams are great for happy snaps, not good for 'POP' (subject separation) or to get good bokeh.

Last edited by wizofoz; 11-13-2011 at 10:58 PM.
11-13-2011, 10:53 PM   #342
Pentaxian
wolfiegirl's Avatar

Join Date: Oct 2011
Location: Outside of Canberra, Australia
Photos: Gallery
Posts: 4,049
Original Poster
Yup.. I remember it took me two whole days of reading and lots of tests on my camera to comprehend that small F number meant small focus area (D0F) and vice versa.

And yet a 50mm 1.4 will give a smaller DOF than a 1.7 50mm. I ask you, how on earth are we supposed to keep a small collection of lenses when there is practically a different lens for every situation that I want to take a photo????
11-13-2011, 10:56 PM   #343
Loyal Site Supporter
wizofoz's Avatar

Join Date: Apr 2009
Location: Melbourne, Outer east.
Photos: Gallery | Albums
Posts: 1,654
QuoteOriginally posted by wolfiegirl Quote
Yup.. I remember it took me two whole days of reading and lots of tests on my camera to comprehend that small F number meant small focus area (D0F) and vice versa.

And yet a 50mm 1.4 will give a smaller DOF than a 1.7 50mm. I ask you, how on earth are we supposed to keep a small collection of lenses when there is practically a different lens for every situation that I want to take a photo????
a 50mm F1.4 can also be used at F1.7. In fact it will probably be better at that F stop because of the way lenses are made. Usually the sweet spot of a lens is when stopped down a little. So, you dont NEED the 1.7. You can have anti LBA and sell it.

The quality of the images the F1.7 lens may please you better though. That si the reason to keep it, and sell the F1.4. There is only 1/3 of a stop difference between the two anyway, so it's marginal.

Last edited by wizofoz; 11-13-2011 at 11:01 PM.
11-13-2011, 11:01 PM   #344
Pentaxian
wolfiegirl's Avatar

Join Date: Oct 2011
Location: Outside of Canberra, Australia
Photos: Gallery
Posts: 4,049
Original Poster
hrmmmm... I currently own two 1.4s and one 1.7. I need to sell one of the 1.4s for sure. But the 1.7 was the first manual I learnt how to use..... so for sentimental reasons I'm not 100% sure I'm willing to part with it atm. Having said that, both are being neglected while I explore all my other lenses atm. I'm so fickle
11-13-2011, 11:07 PM - 1 Like   #345
Pentaxian




Join Date: Jan 2010
Location: Vancouver, BC
Posts: 1,421
QuoteOriginally posted by wolfiegirl Quote
Kiev 4 body - 1984 (plus original case)
Helios 103 - 53/1.8 - 1984
Jupiter 3 - 50/1.5 - 1963
Jupiter 9 - 85/2 - 1968 <--Note that the focusing on the 85/2 is a little stiff but apparently this is not uncommon
Jupiter 9 Finder - no date
Jupiter 11 - 135/4 - 1970
Jupiter 12 - 35/2.8 - 1985
Multiple Turret Finder - no date

All lenses and finders have their original plastic cases.

He's asking $240 for it and coming by tomorrow for me to inspect. If it's good I'm thinking I might wear a low cut top....

The tammy bids all fell through, but I have another 3 on the burner. *shakes head* You'd think after calculating how much I'm in the red I'd stop.... But those all sound like nice lenses to me? Even though I already own a Jup 39 135...

Note: I've cross posted this Q at the soviet lens club but so far no replies

I'm assuming all the lenses will go on the kiev. The kiev has the same m42 mounts right??
Kiev 4 is a rangefinder camera that's supposed to be a copy of the Contax III which has a register distance of 34.85mm, much too short to work with a Pentax which is 45.46mm. If those lenses are for the Kiev 4, then they will not work with your Pentax camera. Bookmark this link; Camera Mounts Sorted by Register you read the chart from top to bottom, left column then the right. Anything above the K mount, DO NOT TOUCH! This means no bidding, don't even window shop. They're cheaper because they can't be used with our cameras. Looking at the list above, I suspect they are indeed lenses for the Kiev 4 and you can end up with lots of pretty paperweights.

Btw, you have a Jupiter 37A 135/3.5.
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!
bid, bit, camera, freebie, fungus, k-mount, k100d, lens, lenses, macro, pentax, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
K-7 froze in video mode, now messed up dedmozaj Troubleshooting and Beginner Help 4 05-18-2011 04:26 PM
WR100mm review messed up mtroute Site Suggestions and Help 5 03-14-2011 03:24 PM
Bh messed up my order again!! Nubi General Talk 3 04-27-2010 09:59 PM
I may have messed up my K-x, please help Wcox Pentax DSLR Discussion 9 04-17-2010 01:40 PM
I messed up with LR Alfisti Digital Processing, Software, and Printing 8 01-07-2010 10:43 AM



All times are GMT -7. The time now is 06:28 AM. | See also: NikonForums.com, CanonForums.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